RESUMEN
BACKGROUND: Natural moisturizing factors such as sodium pyrrolidone carboxylic acid and lactic acid may play an important role in increasing the moisture retention of isolated stratum corneum and reducing the incidence of dry and flaky skin in vivo. Although the precise mechanism of surfactant irritancy is not fully understood, it has been suggested that barrier dysfunction of stratum corneum by surfactants results in skin changes such as scaling, erythema, and even fissuring. OBJECTIVE: We evaluated the effect of sodium pyrrolidone carboxylic acid(NaPCA) and lactic acid(LA) with several non-invasive measuring methods in the irritated skin reaction induced by sodium lauryl sulphate (SLS) in normal persons and atopic dermatitis patients. METHODS: After skin irritation for 24 hours with patch test of 1% SLS on five volar sites of right forearm, we applied nothing(A), 3% LA+3% NaPCA(B), 3% LA(C), 3% NaPCA(D), and vehi cle(E) twice a day respectively. Visual score, transepidermal water loss(TEWL), water holding capa city(WHC), and erythema index were measured at 30 min, 24hr, 48hr and 72hr after patch removal. RESULTS: 1. After 72hr, the visual scores of B and C were significantly lower than that of A(control) in atopic dermatitis patients, and that of C in normal persons was significantly lower than that of A, D, and E. 2. TEWL values of B and C in both the normal (after 72hr) and atopic dermatitis group (after 48hr and 72hr) were significantly lower than that of A. 3. WHC values of B, C, D in both the normal and atopic dermatitis group were significantly higher than that of A after 48hr and 72hr. 4. After 72hr, erythema indices by Mexameter of B, C, and D in both the normal and atopic dermatitis group were significantly lower than that of A and values of C were significantly lower than that of E. In the atopic dermatitis group, values of D were also significantly lower than that of E. 5. The mean visual score was significantly correlated with TEWL value and erythema index of Mexameter (r=0.58, r=0.64) and the TEWL value was significantly correlated with erythema index of Mexameter (r=0.64). CONCLUSION: These results suggest that topical application of a moisturizing factor might improve the surfactant-induced disruption of permeability barrier with improvement of the water holding capacity of the stratum corneum.