Treatment of plantar hyperkeratosis with a combination 10% urea and 8% glycerin topical creamDale Kern, M.S.1; Deanna Carter1; Nathan Fisk, B.A.1; Paul A Cox, Ph.D.2

Nu Skin Research Center, Provo, Utah1; Institute for Ethnomedicine, Provo, Utah2

A recent market research study revealed that among all households with a female interviewed, 29 percentclaimed that either they or another female in the household experienced dry, flaking, or cracked feet not believedto be associated with athlete's foot. This condition, plantar hyperkeratosis, is often seen as thickened, dry skinon the heel of the foot with more severe cases exhibiting fissures and bleeding. Often, the more severe casesharbor a fungal infection (moccasin tenia pedis) that can be confirmed by scraping and KOH or a fungal cul-ture. Causes for plantar hyperkeratosis are many and include genetic defects reflected in skin structure, allergic der-matoses, and paraneoplastic syndromes seen with particular forms of internal malignancy. One form of plantarhyperkeratosis, keratoderma climactericum, is seen in some women during menopause. Many remedies includemoisturizing agents, emollients, and exfoliating agents used to facilitate the removal of thickened skin and pro-mote healing. Frequently, high concentrations of urea, up to 40%, are used but result in topical products thatare unpleasant to use and reduce compliance and, therefore, efficacy.

To evaluate the efficacy of a 10% urea and 8% glycerin topical formulation in treating dry, cracked feet(plantar hyperkeratosis).

Twenty-nine men and women with dry, cracked feet were recruited. At the beginning of the study and prior totreatment, the condition of each foot of each subject was graded according to a photo atlas severity scale.A description of each severity grade is shown in Table 1.

TABLE 1: GRADING SCALE DESCRIPTIONSGrade 0: Fine details, smooth, may have wrinkles, but not dry.Grade 1: Dry lines, slight scaling, and skin thickening.Grade 2: Small fissures, moderate scaling, and skin thickening.Grade 3: Deep fissures, obvious scaling, and skin thickening.Grade 4: Small gaps on fissures, severe scaling, and skin thickening.Grade 5: Big gaps and openings on fissures, bleeding, extreme scaling, and skin thickening.

All subjects were given an ample supply of the test article and instructed to apply a liberal amount to the heelsof both feet twice each day for the duration of the study. The study ran for eight weeks. The test article was atopical formulation containing 10% urea and 8% glycerin in a cream emollient base.

Figures 1-6 are pictures of feet showing a range of smoothness, from no dryness to very severe cracking.

All participants demonstrated remarkable improvement in the condition of their feet. Examples of improvementare shown in Figures 7-9 (these are the pairs of feet, before/after photos). Researchers noted improvementincreased based on severity: the more severe the condition, the greater the improvement. Improvement wasevident after four weeks of treatment and continued through the end of the study (Figure 10). Fissures andcalluses were eliminated, skin was softer and more hydrated, and subject survey data disclosed that all subjectsnoticed an improvement by week four and that 88 percent found the formulation to be effective. Numeroussubjects requested additional test material to continue treatment after the eight-week period. Of note is thatsubjects with a grade of four for severity saw great improvement after four weeks, but after eight weeks theimprovement was not as great. Interviews with study subjects revealed that the great improvement after fourweeks of treatment may have encouraged non-compliance in the following weeks.

Plantar hyperkeratosis was successfully treated with a topical cream formulation containing 10% urea and 8%glycerin. The data suggests that the water-binding, keratolytic, exfoliative, and epidermal-thinning activities ofurea and the skin softening and skin barrier repair properties of glycerin, combine to deliver significant relieffrom plantar hyperkeratosis.

1. Omnibus Survey Results. Incidence of Cracked Feet Among Women in the United State of America (March 2002).2. Deschamps P, Leroy D, Pedailles S, Mandard JC. Keratoderma climactericum (Haxthausen's disease):

clinical signs, laboratory findings and etretinate treatment in 10 patients. Dermatologica 1986;172(5):258–62.3. Schroder W. Urea and its therapeutic possibilities. Fortschr Med 1983;24:101(11):491–3.4. Elewski BE, Haley HR, Robbins CM. The use of 40% urea cream in the treatment of moccasin tinea pedis.

Cutis 2004;73(5):355–7.5. Fluhr JW, Gloor M, Lehmann L, Lazzerinin S, Distante F, Berardesca E. Gycerol accelerates recovery of

barrier function in vivo. Acta Derm Venereol 1999;79(6):418–21.6. Loden M. Role of topical emollients and moisturizers in the treatment of dry skin barrier disorders. Am J Clin

Dermatol 2003;4(11):771–88.7. Gloor M. How do dermatological vehicles influence the horny layer. Skin Pharmacol Physiol 2004;17(6):267–73.

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CONCLUSION

RESULTS

METHODS

OBJECTIVE

BACKGROUND

Figure 1: Grade 0 Figure 2: Grade 1 Figure 3: Grade 2

Figure 4: Grade 3 Figure 5: Grade 4 Figure 6: Grade 5

Figure 7: Before After

Figure 8: Before After

Figure 9: Before After

Figure 10

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