harmonia axyridis ladybug hypersensitivity in clinical...

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OceanSide Publications

IP 6578195178

Harmonia axyridis ladybug hypersensitivity in clinicalallergy practice

David W Goetz MD PhD

ABSTRACT

The imported Harmonia axyridis ladybug infests homes in northern West Virginia from fall through spring causingallergic disease Retrospective single-practice chart reviews were performed (1) all skin prick tests (1400 included ladybug) ina community allergy practice over 4 years and (2) clinical analysis of 400 randomly chosen patients The usual adultaeroallergen skin test panel included ladybug and 57 other allergens Statistics used were contingency table analyses and the-statistic for concordance Home infestation with ladybugs was most common in rural areas but did not predict ladybugsensitization ( 002) Ladybug sensitization and allergy occurred at all ages Ladybug sensitization occurred with 21frequency compared with cat at 24 frequency cockroach at 27 frequency and dust mites at 40 frequency Only ladybugshowed a significant (p 00001) skin test sensitization decreasing from rural (30) mixed (21) to urban (16) homedemographics Isolated single-positive skin tests constituted 10 of dust mites 6 of cockroach 6 of ladybug and 4 ofcat-positive skin tests Skin test concordance was strongest between the pairs ladybugndashcockroach ( 036) cockroachndashdustmite ( 029) and dust mitendashcat ( 025) Ladybug is a major allergen in endemic areas causing rhinoconjunctivitis (8prevalence) asthma (2 prevalence) and urticaria (1 prevalence) Ladybug skin test sensitization is more common in ruralareas and is comparable in frequency and age distribution with cat and cockroach Cockroach and ladybug have a high degreeof skin test concordance A quality commercial ladybug allergen extract and increased ladybug allergen research are needed

(Allergy Asthma Proc 2850ndash57 2007 doi 102500aap2007282956)

Key words Asian lady beetle Harmonia axyrides ladybug rhinoconjunctivitis single-positive skin test

Allergic hypersensitivity to the imported Harmoniaaxyridis ladybug (multicolored Asian ladybeetle)

has been reported in case studies12 Ray and Pence2

published a recent review of H axyridis allergy anddiscussed infestation in the United States after multipleagricultural introductions of the beetle for biologicalpest control during the 20th century

West Virginia is among the states enduring seasonalmarauding swarms of ladybugs for several weeks eachfall Ladybugs preparing for winter hibernation ofteninvade human habitat Home infestation varies fromyear to year and by geographical location Homespainted lighter colors and exterior walls with sun ex-posure are among factors attracting ladybugs to certainhomes The beetles can squeeze through the smallestcracks and best seals into homes Ladybugs typicallydie by the hundreds or thousands during severe homeinfestations requiring frequent vacuuming Ladybugsreaching walls and attics will hibernate until spring-time

In a single-allergist practice in northern West Vir-ginia patient reports of rhinoconjunctivitis asthmaandor urticaria associated with ladybug exposureswere documented from 1998 to 2001 Consequentlythe patient environmental-allergy history was ex-panded to include ladybug allergy Routine skin test-ing for ladybug sensitization was initiated at the be-ginning of 2001 Subsequent experience suggested thatladybug sensitization was common and correlatedwith clinical ladybug allergy to a degree similar to thatseen with cat or other environmental allergens Lady-bug sensitization sometimes presented as an isolatedsingle-positive skin test among the commonly tested 58allergens Ladybug sensitization often was seen in as-sociation with cockroach sensitivity Skin test datafrom 2001 through 2004 were collected and analyzed toconfirm these observations and to better describe clin-ical ladybug sensitization in northern West Virginia Aseparate chart review of 400 patients was performed tocorrelate patient exposures and ladybug skin test sen-sitization with ladybug clinical allergic rhinitisasthma andor urticaria

METHODS

Retrospective Skin Test Chart ReviewIn a retrospective single-practice chart review skin

test results were collected for all allergy patients seenfor 4 calendar years (2001 through 2004) All patients

From Exemplar Allergy and Asthma Morgantown West VirginiaNo funding was providedAddress correspondence and reprint requests to David W Goetz MD PhDExemplar Allergy and Asthma 1063 Maple Drive Suite 1A Morgantown WV26505E-mail address dwgoetzpolnetCopyright copy 2007 OceanSide Publications Inc USA

50 JanuaryndashFebruary 2007 Vol 28 No 1

Property of


IP 6578195178

had been seen by a single allergist who read and re-corded all skin tests Patient age in years home postalzip code and skin tests were anonymously archivedinto a database Patients had been seen in one of threeallergy offices located in Morgantown Clarksburg orWeston WV These communities lie along a 65-milelength of interstate I-79 in northern West Virginia

Aeroallergen skin tests were recorded as positive ornegative in the database Original skin-prick tests hadbeen read 15 minutes after placement and recordedusing a standard protocol3 scale of 0 (no wheal orerythema) 1 (erythema 20 mm) 2 (a wheal 3mm in diameter with surrounding erythema) 3 (awheal 3 mm in diameter with surrounding ery-thema) or 4 (a wheal 3 mm in diameter with pseu-dopods and surrounding erythema) A positive aeroal-lergen skin test was recorded in the database if the skintest was either (1) a 3 or 4 test and the histaminecontrol was 4 or (2) a 2 3 or 4 test and thehistamine control was either 2 or 3 in size Of allhistamine controls for 1902 patients 32 were 2425 were 3 and 541 were 4 in size

Other than the ladybug extract skin-prick testaeroallergen extracts were obtained from ALK-Abello(Round Rock TX) Individual skin-prick tests wereplaced with the AccuSet Device Skin Test System(ALK-Abello) according to the manufacturerrsquos direc-tions A standard panel of 60 aeroallergen skin testsand controls including ladybug was used for mostadult patients and children 6 years of age Individu-alized skin test panels were used when patient histo-ries dictated (eg with extensive food testing) Forchildren 6 years old individualized skin test panelsof 15ndash24 allergens usually were placed using multiple-test devices according to the manufacturerrsquos directions(used initially Quintest from Hollister-Stier SpokaneWA was later replaced by Multi-Test II from ALK-Abello) Ladybug extract became a standard allergenon the pediatric panels approximately halfwaythrough the 4-year period All skin tests included di-luent negative control and prick 10 mgmL of hista-mine control (ALK-Abello) The patientrsquos upper backwas used routinely for testing During the 4-year pe-riod four test allergens changed because of availabilityof extracts For these four newest allergens (privet cornpollen Curvularia and mouse epithelium) a range of426ndash477 skin tests were entered in the database com-pared with the 1355ndash1836 skin tests entered for theother 54 allergens

Ladybug ExtractLive multicolor Asian ladybeetles were collected in-

dividually by hand from several affected homes innorthern West Virginia Ladybug bites are reported byless than 10 of patients and occurred rarely during

collection After collection live ladybugs were frozenuntil extract preparation Frozen ladybugs wereground in a coffee-bean grinder before being weighedand placed in a glass 1-qt French Press (Bodum AGLelystad Netherlands) Saline-albumin-phenol diluent(10 times the ladybug weight ALK-Abello) was addedand the container contents were stirred For 4ndash6 hoursthe mix was periodically stirred at 4degC The FrenchPress strainer was then passed through the mixturetaking care not to compress the solids The strainedaqueous layer was decanted and placed in 10-mL sy-ringes before filtering through 045-m syringe filters(Corning Inc Corning NY) After a final filtrationthrough sterile 02-m Pall syringe filters (Gelman Lab-oratory Ann Arbor MI) the extract was diluted withan equal volume of 50 glycerin (ALK-Abello) to pro-duce the final 120 extract of ladybug in 25 glycerinOver the 4-year period two extract preparations wereused During simultaneous skin testing of two lady-bug-sensitive individuals the two extractions pro-duced similar wheal and flare responses Protein pergram of ladybug extract was 55 for the second ex-traction as determined by methods previously de-scribed3

Descriptive Symptom Chart ReviewIn a 400-patient retrospective single-office chart re-

view charts were chosen randomly from an estimated2000 active charts in the more urban Morgantown WVoffice during early 2006 Patients first seen in 2001 orlater were included Fifty-nine percent of the patientswere seen first in 2005ndash2006 resulting in a majority ofpatients being sampled from outside the pool of pa-tients in the 2001ndash2004 skin test chart review men-tioned previously At entry all patients completed ahistory form including experience with allergy symp-tom triggers and environmental exposures Anony-mously archived data included year of entry age inyears sex home postal zip code patient identificationof allergy symptom triggers and home pests skin teststo ladybug cat dog cockroach and dust mites andallergy diagnoses The entry history form asked fortriggers of allergy symptoms and provided choices ofldquocatrdquo ldquodogrdquo or ldquoother triggersrdquo with a space for write-ins (ldquoladybugrdquo was not a specified choice) When iden-tifying pests patients were given a choice of ldquolady-bugrdquo ldquocockroachrdquo or ldquootherrdquo with a blank space forwrite-ins The patientrsquos final allergy diagnoses (as-signed by the single allergist) were recorded includingany ladybug-induced allergic rhinitis asthma andorurticaria

Statistical ComparisonsPatients were sorted into eight age categories 2

years 2ndash10 years 11ndash20 years 21ndash30 years 31ndash40

Allergy and Asthma Proceedings 51

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IP 6578195178

years 41ndash50 years 51ndash60 years and 60 years Dustmite was considered positive if either (21) or both(79) Dermatophagoides farinae and D pteronyssinuswere positive Geographic analysis of the skin testdatabase began with transformation of each zip codeinto one of three population categories urban mixedurbanrural or rural US Census Bureau data in nu-merical and graphical formats from the United States2000 census was used to categorize each zip code in thedatabase (US Census Bureau Fact sheets for the 2000census factfindercensusgovservletSAFFFacts lastaccessed June 2005) US Census Bureau ldquourbanrdquo areaswere geographically overlaid onto zip code areas Azip code was classified as urban if two-thirds or moreof the zip code area was urban in the 2000 census A zipcode was classified as rural if it contained no urbanareas in the 2000 database Zip codes were classified asldquomixedrdquo urbanrural if they fell between the criteriafor urban and rural Ninety-six percent of urban data-base entries included zip code areas with populationdensities 140 persons per square mile Ninety-sixpercent of rural database entries included zip codeareas with population densities 40 persons persquare mile Mixed urbanrural database entries in-cluded zip code areas with population densities be-tween 40 and 140 persons per square mile 75 of thetime

Descriptive data and contingency table analyses be-tween allergens used the statistical software JMP (SASInstitute Inc Cary NC) Concordance (agreement) ofpositive and negative skin tests between two allergensand agreement between history and clinical findingswere assessed with the -statistic4

RESULTS

Frequency of Positive Skin TestsThe skin test database contained 1902 entries (all

individuals skin tested in 2001 through 2004) Individ-ual patient ages ranged from infancy to 92 years witha mean and median age of 27 and 23 years respec-tively Of the entries 39 included fewer than 10 aller-gen skin tests 96 contained 10ndash17 tests 248 contained18ndash48 tests and 1519 entries contained 49 skin testentries Excluding food allergens the database con-tained 1839 entries of which 440 (24) had no positiveallergen skin tests 229 (12) had a single-positive skintest 165 (9) had two positive skin tests and 1005(55) had three or more positive skin tests

Positive skin test frequencies for tree pollens rangedfrom 4 (pine) to 23 (hickory) with intermediate fre-quencies for cedar 6 mulberry 8 poplar 9privet beech and alder 10 cottonwood 11 sy-camore and elm 12 ash and walnut 13 willowand birch 14 olive 15 oak 17 and maple 21At least one tree was positive 56 of the time Positive

skin test frequencies for grass pollens ranged from 15(Johnson) to 28 (orchard) with intermediate frequen-cies for corn pollen 16 Bermuda 21 Bahia 23fescue and sweet vernal 26 timothy 27 and KYblue and ryegrass 28 At least one grass was positive47 of the time Positive skin test frequencies for weedpollens ranged from 4 (nettle) to 22 (short ragweed)with intermediate frequencies for firebush 8 pig-weed and English plantain 10 mugwort 11 lambsquarters and yellow dock 12 cocklebur 14 andtall ragweed 17 At least one weed was positive 40of the time Positive skin test frequencies for moldsranged from 3 (Rhizopus) to 12 (Alternaria) with in-termediate frequencies for Helminthosporium Fusariumand Aureobasidium 4 Cladosporium and Epicoccum5 Curvularia and Aspergillus fumigatus 6 and Can-dida albicans 7 At least one mold was positive 30 ofthe time

Positive skin test frequencies for animal dandersranged from 6 (mouse and dog) to 24 (cat) withintermediate frequencies for rabbit 7 and horse 9Mixed feathers were positive in 3 of database entriesPositive skin test frequencies for insects included 21ladybug 27 cockroach and 40 dust mites (34 Dfarinae and 37 D pteronyssinus)

The number of database entries for the eight agecategories were 2 years 78 2ndash10 years 517 11ndash20years 282 21ndash30 years 249 31ndash40 years 224 41ndash50years 232 51ndash60 years 183 and 60 years 137 Theage-specific frequencies of positive skin tests were sim-ilar for ladybug and major aeroallergens (Fig 1) La-dybug-sensitized individuals had an age distributionalmost identical to the full population ranging frominfancy to 91 years with a mean and median age of 28and 23 years respectively The ages were similar bydemographics urban (1ndash75 years mean 310 years)mixed (1ndash71 years mean 227 years) and rural (1ndash91years mean 274 years) Although most patients weretested with a specific allergen panel the 2-year-oldage group was tested more often with individuallychosen allergens In Fig 1 only cockroach dust mitescat and ladybug were skin tested frequently in this agegroup (26 ladybug and 72 times for the others) Com-pared with cockroach dust mites and cat the higherladybug positive skin test frequency in the 2-year-oldgroup is likely caused by a testing selection bias

Isolated Single-positive Skin TestsOf the 229 isolated single-positive skin tests in the

aeroallergen database dust mite was single positive 72times (10 of 728 positive dust mite tests in the data-base) cockroach was single positive 28 times (6 of491 positive tests) ladybug was single positive 18times (6 of 299 positive tests) cat was single positive19 times (4 of 440 positive tests) maple was single


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IP 6578195178

positive 8 times (3 of 316 positive tests) Candida wassingle positive 6 times (7 of 92 positive tests) andother allergens were single positive 5 times Of theseisolated single-positive skin test entries 70 contained48 allergen skin tests and 30 of the entries had8ndash47 skin tests The ladybug single-positive individu-als ranged from 1 to 85 years of age with a mean of277 years Their homes were more rural (58) than allladybug-positive patients (45) or all patients (35) Ifstatistically random the expected frequency of lady-bug (or any other allergen) among the 229 single-pos-itive skin tests is approximately 5 times (2 of singlepositives) Only four single-positive allergens exhib-ited greater than twice the random frequency dustmites 31 cockroach 12 and ladybug and cat each8 of the isolated single positives

Concordance of Ladybug and Other Allergen-Positive Skin Tests

Concordance (agreement) between pairs of allergensin the database was addressed first using 2 2 con-

tingency table analyses and the -statistic (Table 1)Ladybug skin tests were most concordant with cock-roach ( 036) and dust mites ( 020) The rsquos forladybug with Bermuda (016) willow (016) timothy(012) and Johnson grass pollen (011) were intermedi-ate and the average for the other 51 allergens was005 Cockroach skin tests were concordant with lady-bug ( 036) and dust mite ( 029) skin tests withsmaller -values for other allergens For comparisonstrong agreement was seen as expected for two rag-weed species ( 067) Within a class willow wasconcordant with other trees (average 029) andshort ragweed was concordant with other weeds (av-erage 030) Ladybug skin test concordance withcockroach ( 036) is uniquely strong among lady-bug-allergen pairs

A second indication of concordance between twoallergen skin tests may be their isolated dual-positiveoccurrence There were 165 database entries with onlytwo positive allergen skin tests Of these 24 includedladybug among the 51ndash57 skin tests per entry Ladybug

Figure 1 Percent allergen sensitization by age group Database entries 2 years (1ndash72) 2ndash10 years (278ndash504) 11ndash20 years (232ndash276)21ndash30 years (191ndash241) 31ndash40 years (181ndash216) 41ndash50 years (191ndash225) 51ndash60 years (144ndash171) and 60 years (106ndash133) Ages 6 yearsand 2ndash6 years usually skin tested with the adult and pediatric standard panel respectively Age 2 years individual allergens chosenlimiting comparisons among allergens for this youngest age group

Table 1 Allergen pair and percent of isolated dual-positive skin tests

Dual-Positive Skin Tests

Cockroach Dust Mite Cat Cockroach Dust Mite Cat

Ladybug 036 020 009 7 2 1Cockroach 029 014 15 2Dust mite 025 8

-statistic for the allergen-pair concordance (agreement) in the full skin test database (if identical 10)Statistically random expected value is 1


Property of


IP 6578195178

most often paired with cockroach (11 times) dust mite(3 times) and Alternaria (2 times Table 1) If statisti-cally random ladybug (or any other allergen) wouldbe present approximately three times among the 165pairs while the expected frequency for a specific pairof allergens is 1 In 59 entries cockroach was dual-positive with dust mite (25 times) ladybug (11 times)and cat (4 times) In 67 entries dust mite was dual-positive with cockroach (25 times) cat (13 times) andladybug (3 times) In 31 entries cat was dual-positivewith dust mite (13 times) and cockroach (4 times)Other allergens were infrequently part of an isolateddual-positive pair maple (11 times) Alternaria (10times) oak (10 times) and others (average 17 times)Among all dual-positive entries 79 contained 48 ormore allergen skin tests and 21 contained between 8and 47 skin tests Dust mites cockroach ladybug andcat were together present in 122 of 165 (74) isolateddual-positive skin tests which was 10 times the ran-domly expected frequency Parallel to the contingencytable analysis results ladybug and cockroach ( 036)showed unusually frequent pairing (7 of all isolateddual-positive skin tests) Two other allergen pairsshowed frequent pairing dust mitendashcockroach (15 ofdual-positives 029) and dust mitendashcat (8 ofdual-positives 025 Table 1)

Geographic Variation of Ladybug SensitizationOf all aeroallergens in the database only ladybug

(Fig 2) showed a pattern of significant decreasing skintest frequency that was highest (30) in rural interme-diate (21) in mixed and lowest (16) in urban zipcodes (p 00001) The opposite pattern of significant(p 005) increasing skin test frequencies from lowestin rural to highest in urban zip codes was seen for 17allergens (alder ash birch maple olive KY blue fes-cue orchard ryegrass sweet vernal timothy yellowdock lambs quarters mugwort short ragweed tallragweed and cat) and was highly significant (p 00001) only for cat and ash pollen (pollen data notshown)

Symptom Review of Ladybug AllergyAs anticipated the 400-chart descriptive symptom

review that was limited to the Morgantown office in2006 was more urban (58 versus 42) than the skintest chart review from 2001 to 2004 Patient-identifiedallergy symptom triggers included cats (23) and dogs(16) with write-ins greater than 1 including lady-bugs (1) feathers (2) rabbits (1) and horses (1)Cockroaches received no write-ins as a trigger Patientsidentified ladybugs as pests in 42 of homes (Table 2)but identified cockroaches in only 2 and write-ins1 included ants (4) and spiders (3)

Among the 400 charts 305 had been skin tested to allfive antigens ladybug cat dog cockroach and dustmite Positive skin tests for ladybug cockroach cat anddust mite were very comparable with the larger 2001ndash2004 skin test analysis (eg ladybug 20 versus 21frequency) even though this mix of individuals was moreurban and 59 were not contemporaneous with those inthe larger analysis (Table 2) The -agreement for pairs ofallergen skin tests mirrored the results of Table 1 lady-bugndashcockroach ( 035) ladybugndashdust mite ( 020)ladybugndashcat ( 008) cockroachndashdust mite ( 026)cockroachndashcat ( 015) and dust mitendashcat ( 038)

Among the 400 charts reviewed a final diagnosis ofallergic rhinitis was made in 62 asthma in 28 andurticaria in 16 with some individuals having multi-ple diagnoses Other diagnoses with 1 prevalenceincluded food allergy (10) immune deficiency (4)contact dermatitis (4) hymenoptera hypersensitivity(4) atopic dermatitis or rash (4) drug reactions(2) cholinergic rhinitis (1) delayed pressure urti-caria (1) and environmental intolerance (1) Lady-bug allergic rhinitis was diagnosed in 8 of the 400patients A diagnosis of ladybug asthma was made in2 and a diagnosis of ladybug urticaria was made in1 (Table 2)

Figure 2 Percent allergen sensitization by urbanization of pa-tientrsquos domicile zip code Database entries 413ndash417 rural 429ndash546 mixed 558ndash774 urban p 00001


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IP 6578195178

In keeping with the findings of Fig 2 among thethree demographic groups the rates of positive lady-bug skin tests were greatest in rural areas (19 urban16 mixed and 25 rural) whereas the opposite trendwas seen for cat skin tests (32 urban 22 mixed and21 rural) Ladybugs were identified as pests moreoften in rural areas (33 urban 47 mixed and 60rural) Among the 400 patients in urban mixed andrural areas the frequency of diagnosis for all allergicrhinitis (63 56 and 64) asthma (26 32 and 28) andurticaria (15 21 and 16) were similar But the fre-quency of ladybug allergic rhinitis (6 8 and 11)ladybug asthma (1 0 and 3) and ladybug urticaria(1 0 and 1) were greater in rural areas

The 60 ladybug skin testndashpositive patients did notdiffer from all skin-tested patients in either year ofentry age or sex (Table 2) Consistent with the -val-ues mentioned previously and findings in Table 1ladybug skin testndashpositive patients were more likely tobe skin test positive also to cockroach (67 versus 32)and dust mites (60 versus 38) Ladybug skin testndashpositive patients identified ladybugs as home pests nomore often than the whole population (42 versus42) The lack of association between ladybug skin

tests and ladybug pest identification was confirmedfurther by a 002 (p 073) If the 166 patientswho reported a ladybug pest problem were comparedwith all 400 patients the rates of positive skin testswere comparable for ladybug (19 versus 20) cat(24 versus 27) cockroach (32 versus 32) anddust mites (35 versus 38) The positive predictivevalue (PPV) of having ladybugs as pests was less thanchance (42) for predicting positive skin tests to lady-bugs Similarly the PPV of having ladybugs as pestswas no better than chance for predicting ladybug al-lergic rhinitis (47) ladybug asthma (50) and lady-bug urticaria (33)

The totality of clinical evidence resulted in the diag-nosis of ladybug allergic rhinitis in 30 (50) of ladybugskin test-positive patients (Table 2) A diagnosis ofladybug asthma was made in 10 of those patientswho were ladybug skin test positive and a diagnosis ofladybug urticaria was made in 5 Consistent with thefindings of Fig 2 the demographic distributions forthe 31 ladybug-allergic patients and the 60 ladybugskin testndashpositive patients were more rural than that ofthe full review group of 400 (36 30 and 23 respec-tively)

Table 2 Retrospective single-office chart review results by group

Group Total SkinTested

LadybugSkin TestPositive

LadybugAllergy

Patient History by Population GroupPatients 400 305 60 31Age range (yr) 1ndash90 1ndash90 1ndash76 1ndash76Mean age (yr) 336 316 321 271Female 57 54 53 52Urban home 58 56 53 45Mixed home 19 21 17 19Rural home 23 23 30 36Cat triggers symptoms 23 28 30 39Dog triggers symptoms 16 20 20 23Ladybug triggers symptoms 1 2 8 16Ladybug pests reported 42 44 42 48Cockroach pests reported 2 2 3 6

Skin-Test Results and DiagnosesLadybug-positive skin test 20 100 100Cockroach-positive skin test 32 67 58Dust mitendashpositive skin test 38 60 52Cat-positive skin test 27 35 35Allergic rhinitis 62 76 93 97Asthma 28 33 33 39Urticaria 16 11 13 10Ladybug allergic rhinitis 8 10 50 97Ladybug asthma 2 2 10 19Ladybug urticaria 1 1 5 10


Property of


IP 6578195178

Among the full group of 400 patients only 5 patientswrote in ladybug as a trigger and all 5 were among theskin testndashpositive patients diagnosed as ladybug aller-gic For prediction of a positive skin test the PPV ofpatientsrsquo identification of ladybugs as a trigger was100 Cats were an identified allergy trigger by 225of patients and dogs were an identified allergy triggerby 155 However for prediction of a positive skintest the PPV of patientsrsquo identification of cats or dogsas a trigger was about the same as chance (54 and 53)

DISCUSSIONTwo retrospective reviews provide a descriptive

overview of ladybug hypersensitivity in this West Vir-ginia allergy practice The smaller chart review sam-pled patient history and diagnosis of ladybug allergyand the larger 4-year inclusive skin test study con-trasted the results of ladybug skin testing to 57 com-monly skin-tested allergens Ladybug-allergic patientsin northern West Virginia most often present with falland spring allergic rhinoconjunctivitis and less oftenwith asthma or urticaria Clinical experience in thisallergy practice previously suggested that the popula-tion burden of allergic disease attributable to ladybugscan be as great as that seen with cockroaches or catsThis review confirms that 20 of skin-tested patientsin endemic areas are ladybug hypersensitive and atleast one-half (10) are ladybug allergic

Based on the 4-year skin test data in northern WestVirginia ladybug sensitization is prevalent (21)among allergy patients and similar to cat (24) andcockroach (27) sensitization (Fig 1) These skin testfrequencies are very similar to recently reported Na-tional Health and Nutrition Examination Survey III(NHANES III) data for 9 aeroallergens and over 10000skin tests in the general US population aged 6ndash59years5 Except for a greater dust mite sensitivity in theallergy clinic population the rates of positive skin testsfor the nine aeroallergens are very similar in the twodata sets (NHANES III versus this database review)dust mite (28 versus 40) cockroach (26 versus27) cat (17 versus 24) rye grass (27 versus28) short ragweed (26 versus 22) Bermuda grass(18 versus 21) oak (13 versus 17) Alternaria(13 versus 12) and Russian thistle (15 inNHANES III) versus Lambs quarters (12 in this da-tabase) The NHANES III age distribution results werereported for six aeroallergens and the age of peaksensitization was similar in the two data sets(NHANES III versus this database review) Alternaria(10ndash20 years versus 10ndash20 years) Bermuda grass(20ndash30 years versus 10ndash40 years) cat (20ndash30 yearsversus 20ndash30 years) oak (20ndash30 years versus 20ndash30years) ragweed (20ndash30 years versus 20ndash30 years) andrye grass (20ndash40 years versus 20ndash30 years)

Isolated single-positive skin tests occurred in 12 oftested patients making this a common event Fourallergensmdashdust mite cockroach ladybug and catmdashaccounted for 60 of such events among the usuallytested 58 allergens The single-positive skin test repre-sented 10 of all positive skin tests for dust mites 6of cockroach and ladybugndashpositive skin tests and 4of all positive cat skin tests The finding of 50 lady-bug allergy among ladybug skin testndashpositive patientsin the smaller chart review rules out the possibility thatsingle-positive skin tests are false positive tests as hasbeen reported for mesquite tree pollen6 Frequent iso-lated single-positive skin tests for ladybug (dust mitescockroach and cat) raise potential research questionsof unique and particularly strongly allergenic epitopesgenetic host susceptibilities and vagaries of humanecology

The clinical correlation of ladybug with cockroachsensitization was confirmed in both retrospective re-views The strong agreement of ladybug and cockroachskin test results was both statistically apparent ( 036 and 035) and further supported by the high per-centage of ladybugndashcockroach pairings in Table 2 andby isolated dual-positive skin tests in Table 1 The fourallergensmdashdust mites cockroach ladybug and catmdashndashwere prominent allergens in the skin test databaseEach (1) had a total frequency of positive skin tests of20 (2) were the most frequent isolated single-pos-itive skin tests 4ndash10 of the time (3) were a constituentin 74 of the isolated dual-positive skin tests and (4)exhibited highly coincident pairings for ladybugndashcock-roach dust mitendashcockroach and dust mitendashcat (Fig 1Tables 1 and 2) Cross-reactivity among other insectshas been researched extensively and might similarlyaccount for the ladybugndashcockroach association butconfirmation awaits additional research

Ladybug allergy and skin test sensitization arepresent in all age groups (Fig 1 Table 2) Unlike anyother aeroallergen ladybug sensitization was greatestin rural home areas (Fig 2) Until additional research isavailable perhaps the best hypothesis for this uniquegeographic prevalence for ladybug sensitization in ru-ral areas is that ladybug exposures are greater in morerural areas perhaps because of the insect preferencefor rural environments This is consistent with patientreports of extreme infestations of cabins and homes indeep-wooded areas and the insectrsquos known behavior inits native territories2

In contrast to ladybug allergy cat allergy was morecommon in urban areas in both reviews In contrast toa strong PPV for identification of ladybugs as an al-lergy trigger identification of cats or dogs as an allergytrigger was no better than chance at identifying thosewho were skin test positive to either animal This mis-identification of animals as allergy triggers may resultfrom forceful publicizing of animal allergy and ani-


Property of


IP 6578195178

malsrsquo high visibility Cockroaches were never identi-fied as an allergy trigger and rarely were identified asa pest

The prevalence of ladybug home infestation was 42overall and greatest in rural homes Ladybug-positiveskin tests and ladybug allergies also were more com-mon in rural areas However identification of ladybugpests in a home was no better than chance in predictinga positive skin test to ladybug or clinical allergy toladybugs Apparently allergic sensitization to lady-bugs is a result of more exposures than just those athome Unlike cockroaches that were acknowledged asa pest only 2 of the time ladybugs are highly visiblewhen not in hibernation Despite their visibility from2001 to 2006 ladybugs were seldom recognized as trig-gers of allergy symptoms Only after discussion ofpotential allergen triggers with the physician did mostpatients entertain the possibility Once considered pa-tients with ladybug allergy often linked their symp-toms with ladybug exposures at home school daycarevisits with relatives or in other settings Just as withcat dust mites cockroach and other allergens skintesting to ladybug then provided significant posttestconfidence in diagnosis and recommendations for al-lergen avoidance and treatment As the notoriety ofladybugs as an allergen trigger grows in public aware-ness the identification of ladybugs as a trigger maywell rise to that level of misidentification currentlyseen for cats and dogs

In this allergy practice between 2001 and 2004 aller-gen vaccine therapy was prepared for 481 patients ofwhom 88 (18) received allergen vaccine therapy in-cluding ladybug plus any other clinically relevant al-lergens All 88 patients strongly correlated their allergysymptoms with ladybug exposures Although out-comes for ladybug immunotherapy are anecdotal theclinical improvement seen with ladybug immunother-apy was as great as or greater than that with cats(which is usually highly successful) No adverse reac-tions occurred No individuals reaching and maintain-ing maintenance immunotherapy reported failure Allwere able to tolerate greater ladybug exposures withfewer allergen symptoms At the extreme several in-

dividuals unable to live in their home during ladybuginfestation were able to return to live in their homes

These retrospective reviews extend the clinical expe-rience with ladybug allergy from the previously re-ported individual cases and spotlight ladybugs as asignificant allergen in allergy practices within endemicareas Allergen sensitization and clinical importance iscomparable with cat and cockroach in West VirginiaLadybug allergy presents most often as allergic rhino-conjunctivitis (8 prevalence) less often as asthma(2) and least often as urticaria (1) Ladybug sensi-tization and allergy occurs at any age and are greater inpatients living in rural versus urban environmentsLadybug home infestation was more common in ruralareas but did not predict ladybug sensitization or al-lergy Isolated single-positive skin tests are fairly com-mon not only for ladybug but also for dust mitescockroach and cat Cockroach and ladybug have ahigh degree of skin test concordance Availability of aquality commercial ladybug allergen extract is para-mount for future patient care Ladybug allergen inves-tigations and controlled prospective studies of ladybugallergy are needed

REFERENCES1 Yarbrough JA Armstrong JL Blumberg MZ et al Allergic rhi-

noconjunctivitis caused by Harmonia axyridis (Asian lady beetleJapanese lady beetle or lady bug) J Allergy Clin Immunol104704ndash705 1999

2 Ray JN and Pence HL Ladybug hypersensitivity Report of acase and review of the literature Allergy Asthma Proc 25133ndash136 2004

3 Reid MJ Nish WA Whisman BA et al HLA-DR4-associatednonresponsiveness to mountain-cedar allergen J Allergy ClinImmunol 89593ndash598 1992

4 Agresti A Categorical Data Analysis New York John Wiley andSons Inc 1990 365ndash370

5 Arbes SJ Gergen PJ Elliott L and Zeldin DC Prevalences ofpositive skin test responses to 10 common allergens in the USpopulation Results from the Third National Health and Nutri-tion Examination Survey J Allergy Clin Immunol 116377ndash3832005

6 Kelso JM Interpretation of isolated positive skin-test results formesquite tree pollen J Allergy Clin Immunol 114452ndash4542004 e


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IP 6578195178

had been seen by a single allergist who read and re-corded all skin tests Patient age in years home postalzip code and skin tests were anonymously archivedinto a database Patients had been seen in one of threeallergy offices located in Morgantown Clarksburg orWeston WV These communities lie along a 65-milelength of interstate I-79 in northern West Virginia

Aeroallergen skin tests were recorded as positive ornegative in the database Original skin-prick tests hadbeen read 15 minutes after placement and recordedusing a standard protocol3 scale of 0 (no wheal orerythema) 1 (erythema 20 mm) 2 (a wheal 3mm in diameter with surrounding erythema) 3 (awheal 3 mm in diameter with surrounding ery-thema) or 4 (a wheal 3 mm in diameter with pseu-dopods and surrounding erythema) A positive aeroal-lergen skin test was recorded in the database if the skintest was either (1) a 3 or 4 test and the histaminecontrol was 4 or (2) a 2 3 or 4 test and thehistamine control was either 2 or 3 in size Of allhistamine controls for 1902 patients 32 were 2425 were 3 and 541 were 4 in size

Other than the ladybug extract skin-prick testaeroallergen extracts were obtained from ALK-Abello(Round Rock TX) Individual skin-prick tests wereplaced with the AccuSet Device Skin Test System(ALK-Abello) according to the manufacturerrsquos direc-tions A standard panel of 60 aeroallergen skin testsand controls including ladybug was used for mostadult patients and children 6 years of age Individu-alized skin test panels were used when patient histo-ries dictated (eg with extensive food testing) Forchildren 6 years old individualized skin test panelsof 15ndash24 allergens usually were placed using multiple-test devices according to the manufacturerrsquos directions(used initially Quintest from Hollister-Stier SpokaneWA was later replaced by Multi-Test II from ALK-Abello) Ladybug extract became a standard allergenon the pediatric panels approximately halfwaythrough the 4-year period All skin tests included di-luent negative control and prick 10 mgmL of hista-mine control (ALK-Abello) The patientrsquos upper backwas used routinely for testing During the 4-year pe-riod four test allergens changed because of availabilityof extracts For these four newest allergens (privet cornpollen Curvularia and mouse epithelium) a range of426ndash477 skin tests were entered in the database com-pared with the 1355ndash1836 skin tests entered for theother 54 allergens

Ladybug ExtractLive multicolor Asian ladybeetles were collected in-

dividually by hand from several affected homes innorthern West Virginia Ladybug bites are reported byless than 10 of patients and occurred rarely during

collection After collection live ladybugs were frozenuntil extract preparation Frozen ladybugs wereground in a coffee-bean grinder before being weighedand placed in a glass 1-qt French Press (Bodum AGLelystad Netherlands) Saline-albumin-phenol diluent(10 times the ladybug weight ALK-Abello) was addedand the container contents were stirred For 4ndash6 hoursthe mix was periodically stirred at 4degC The FrenchPress strainer was then passed through the mixturetaking care not to compress the solids The strainedaqueous layer was decanted and placed in 10-mL sy-ringes before filtering through 045-m syringe filters(Corning Inc Corning NY) After a final filtrationthrough sterile 02-m Pall syringe filters (Gelman Lab-oratory Ann Arbor MI) the extract was diluted withan equal volume of 50 glycerin (ALK-Abello) to pro-duce the final 120 extract of ladybug in 25 glycerinOver the 4-year period two extract preparations wereused During simultaneous skin testing of two lady-bug-sensitive individuals the two extractions pro-duced similar wheal and flare responses Protein pergram of ladybug extract was 55 for the second ex-traction as determined by methods previously de-scribed3

Descriptive Symptom Chart ReviewIn a 400-patient retrospective single-office chart re-

view charts were chosen randomly from an estimated2000 active charts in the more urban Morgantown WVoffice during early 2006 Patients first seen in 2001 orlater were included Fifty-nine percent of the patientswere seen first in 2005ndash2006 resulting in a majority ofpatients being sampled from outside the pool of pa-tients in the 2001ndash2004 skin test chart review men-tioned previously At entry all patients completed ahistory form including experience with allergy symp-tom triggers and environmental exposures Anony-mously archived data included year of entry age inyears sex home postal zip code patient identificationof allergy symptom triggers and home pests skin teststo ladybug cat dog cockroach and dust mites andallergy diagnoses The entry history form asked fortriggers of allergy symptoms and provided choices ofldquocatrdquo ldquodogrdquo or ldquoother triggersrdquo with a space for write-ins (ldquoladybugrdquo was not a specified choice) When iden-tifying pests patients were given a choice of ldquolady-bugrdquo ldquocockroachrdquo or ldquootherrdquo with a blank space forwrite-ins The patientrsquos final allergy diagnoses (as-signed by the single allergist) were recorded includingany ladybug-induced allergic rhinitis asthma andorurticaria

Statistical ComparisonsPatients were sorted into eight age categories 2

years 2ndash10 years 11ndash20 years 21ndash30 years 31ndash40


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harmonia axyridis ladybug hypersensitivity in clinical...

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