A Study to Assess the Occlusivity and Moisturization Potential of Three Topical Corticosteroid Products Using the Skin Trauma After Razor Shaving (STARS) Bioassay
May 2014 | Volume 13 | Issue 5 | Original Article | 582 | Copyright © May 2014
Leon H. Kircik MD FAAD
Indiana University School of Medicine, Indianapolis, IN Mount Sinai Medical Center, New York, NY Physicians Skin Care, PLLC, Louisville, KY
Dysfunction of the epidermal barrier is generally considered a precursor of cutaneous inflammation that can directly contribute to the pathogenesis of skin diseases, notably atopic dermatitis (AD). We also know that topical corticosteroids may actually impair the epidermal barrier by interfering with epidermal lipid synthesis. Therefore, it is important to utilize topical corticosteroids in vehicles that will help at least to enhance the already disrupted epidermal barrier in atopic dermatitis patients. Two studies of identical design were conducted to determine and compare the occlusivity and moisturizing potential of three topical corticosteroid products when applied to skin whose barrier integrity has been disrupted by dry shaving. Findings in both studies showed the clocortolone pivalate cream decreased TEWL better than non-treatment or treatment with hydrocortisone butyrate lotion. Skin surface hydration increased significantly (P<0.001) in all three treated sites, compared to the non-treated damaged control and non-treated normal skin. Clocortolone pivalate cream increased skin surface hydration significantly (P<0.001) better than hydrocortisone butyrate lipocream or hydrocortisone butyrate lotion. These studies showed that clocortolone pivalate cream enhances barrier function by providing occlusion.
While understanding of the structure and function of the stratum corneum (SC) and epidermal barrier function has evolved tremendously over the last several decades, and especially over the last 15 years,1 confusion and misinformation still persist. Dysfunction of the epidermal barrier is generally considered a precursor of cutaneous inflammation that can directly contribute to the pathogenesis of skin diseases, notably atopic dermatitis (AD).2,3 Topical steroids are standard of care in treatment of atopic dermatitis. However, we also know that topical corticosteroids may actually impair epidermal barrier by interfering with epidermal lipid synthesis.4,5 In addition to that, various penetration enhancers in the topical steroid formulations also contribute to the impairment of the epidermal barrier.4 Therefore, it is important to utilize topical corticosteroids in vehicles that will help at least to enhance the already disrupted epidermal barrier in atopic dermatitis patients. In this regard, these studies were designed to determine the hydrating effects of clocortolone pivalate cream 0.1% (Cloderm Cream, Promius Pharma). J Drugs Dermatol.
Corticosteroids and TEWL
Transepidermal water loss (TEWL) is a marker for epidermal barrier dysfunction that has been shown to independently correlate with atopic dermatitis severity.5 Although topical corticosteroids are frequently used to treat atopic dermatitis, studies dating back more than a decade have suggested that certain topically-applied corticosteroids can increase TEWL and contribute to epidermal barrier dysfunction.6,7 One study suggested that just three weeks of topical betamethasone application compromised the barrier and induced epidermal atrophy.8 One investigation of the cutaneous effects of topical corticosteroid application in mice identified, "a progressive increase in transepidermal water loss accompanied by a diminution in the SC intercellular lipid lamellae, which showed a normal structure of individual lamella."7
However, such findings contradict those from studies of certain topical corticosteroid formulations that are shown to improve skin hydration and reduce TEWL.9,10 In addition, detrimental effects (eg, contact sensitization) of a given formulation may have less to do with the corticosteroid itself than with the topical vehicle in which it is delivered.11
STUDY DESIGN AND RATIONALE
Each study involved 18 subjects 23–55 years of age. Subjects had no skin conditions other than dry skin on the volar forearms. The studies compared the effects of three different corticosteroid formulations and non-treatment on hydration and transepidermal water loss. The studied formulations were clocortolone pivalate cream 0.1%, hydrocortisone butyrate lotion 0.1% (Locoid® lotion, Onset), and hydrocortisone butyrate lipocream 0.1% (Locoid® lipocream, Onset).