Disaggregation of Corneocytes from Surfactant‐treated Sheets of Stratum Corneum in Hyperkeratosis on Psoriasis, Ichthyosis Vulgaris and Atopic Dermatitis

Abstract

To elucidate the pathogenesis of impaired barrier function and the influence of surfactant on the stratum corneum in hyperkeratosis, we investigated morphological alterations of the corneocytes with soap solution. Groups of five patients each with psoriasis vulgaris (PV), ichthyosis vulgaris (IV), atopic dermatitis (AD), and normal controls were examined. Four samples of the horny layer were obtained from the same site by cyanoacrylate adhesive biopsy. The first sample was used for the superficial layer, and the fourth, for the basal horny layers. Each sample was agitated in 1% stirred soap solution at 60 degrees C. The number and size of isolated corneocytes and the morphologic changes were investigated. The release of corneocytes was greater and the swelling and morphological changes of corneocytes exposed to soap solutions were less in PV and AD than in IV or in healthy subjects. In IV, the release was markedly less than in controls. The release and swelling were greater in the superficial than in the basal horny layers. It was concluded that the cohesiveness of corneocytes was probably less in PV and AD and greater in IV than in normals. It was also suggested that the cohesion of corneocytes from the superficial horny layer was less than that from the deep layer. The permeability of the cornified envelope in PV and AD patients was less than in IV or healthy subjects. It was confirmed that highly potent soaps induce loss of many corneocytes and reduce the barrier function of the stratum corneum.

Cellular Changes that Accompany Shedding of Human Corneocytes

“…Changes in lipid composition across the SC, particularly in cholesterol sulfate content, have been proposed to regulate desquamation (Epstein , et al ., 1981, Long , et al ., 1985, Rehfeld , et al ., 1988). Moreover, mild organic solvent and/or detergent treatment of SC generates individual corneocytes (Chapman , et al ., 1991, Shukuwa , et al ., 1997). Because two ceramidase isoforms, acidic (aCDase) and alkaline CDase are expressed in SC (Wertz , et al ., 1990, Houben , et al ., 2006), either or both could account for the substantial amounts of sphingosine and ω-hydroxy fatty acids that are present in SC (Uchida , et al ., 2008).…”

Consensus Guidelines for the Treatment of Atopic Dermatitis in Korea (Part I): General Management and Topical Treatment

“…The recommendations for bathing are summarized in Table 2 2 4 9 10 11 12 13 . Generally, a maximum bathing frequency of once per day is recommended 2 .…”

“…Nonsoap cleansers (e.g., syndets, aqueous solutions), which have a neutral or low pH and are less allergenic, nonirritating, and fragrance-free, are recommended. Soap-based cleansers, which have a high pH and contain surfactants, should be avoided, because they can cause dry skin, irritation, and contact dermatitis 11 12 13 . Antiseptic-containing cleansers are not recommended due to the limited duration of action of antiseptics and limited clinical data regarding their effectiveness 3 .…”

Treatment principles of atopic dermatitis

“…Finally, it is advisable to recommend soap for daily cleansing of the skin. Highly potent soap is not recommended as it reduces barrier function by increased loss of corneocytes; 27 however, regular use of a mild soap, sometimes in conjunction with an antiseptic, improves eczema 28,29 …”