INTRODUCTION
Keratosis pilaris (KP) is a common benign dermatosis affecting an estimated 50-80% of adolescents and 40% of adults worldwide.1 KP is diagnosed clinically based on the presence of folliculocentric keratotic papules or pustules with surrounding erythema, usually located on the proximal extensor surfaces of extremities.2 The etiology of KP is unknown but theorized to result from an inherited or acquired defect in the keratinization process, which results in follicular plugging, local inflammation, and retention hyperkeratosis.2,3 Despite its largely asymptomatic nature, KP can be associated with significant erythema or skin texture changes that are bothersome or cosmetically distressing to patients.4 Therapies for KP can improve the affected skin's appearance and relieve associated psychosocial stress; KP patients have reported embarrassment, decreased self-confidence, and social dysfunction related to their skin.5 KP may improve over time, but treatment options include topical emollients and keratolytics (typically containing lactic acid, salicylic acid, or urea), topical retinoids (particularly tazarotene), and other exfoliants, anti-inflammatory medications, or laser therapies.2,6,7
Urea-containing preparations have been studied in a variety of dermatologic conditions including KP, KP-related conditions such as atopic dermatitis and ichthyosis vulgaris, psoriasis, xerosis, and hyperkeratotic-type tinea pedis.4,8-11 Urea is a component of the natural moisturizing factors with humectant, emollient, and keratolytic properties. At low concentrations (less than or equal to 10%), urea-based preparations increase skin hydration and moisturization, while high-concentration preparations (>10%) are exfoliating and can improve hyperkeratosis.9 Urea is generally well tolerated; mild and transient side effects reported at high doses include a stinging or burning sensation.8,11 With these properties in mind, a clinical study evaluated the therapeutic effects and tolerability of a moisturizing cream formulated with 20% urea (20% urea cream) for KP.
MATERIALS AND METHODS
An open-label, prospective, non-comparative, single center study was conducted to evaluate 20% urea cream in KP. Thirty participants aged 18 to 65 years old with KP on their arms or legs completed the study (Table 1). After a 5-day washout period, all participants applied 20% urea cream once daily to affected areas of KP. There were 3 visits during the study: initial/baseline, week 1, and week 4. At the baseline visit as well as the follow-up visits, digital photographs were taken in a standardized fashion. Photographs were then evaluated by multiple expert clinical graders (PhD, BS, MHI) for appearance of smoothness/texture
