Like other topical corticosteroids, clobetasol propionate has anti-inflammatory, antipruritic, and vasoconstrictive properties. The mechanism of the anti-inflammatory activity of the topical steroids, in general, is unclear. However, corticosteroids are thought to act by the induction of phospholipase A 2 inhibitory proteins, collectively called lipocortins. It is postulated that these proteins control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes by inhibiting the release of their common precursor , arachidonic acid. Arachidonic acid is released from membrane phospholipids by phospholipase A2.
The most frequent adverse reactions include burning, stinging, rash, red, bumpy rash, redness, itching, moderate tingling or prickling feeling, and allergic rash. Local adverse reactions that have been reported with topical corticosteroids include itching, irritation, dryness, folliculitis (swelling of the hair follicles), hypertrichosis (excessive hair growth), acneiform eruptions (acne or rashes resembling acne), hypopigmentation (loss of skin color), perioral dermatitis (rash around the mouth), allergic contact dermatitis (rash), secondary infections, skin atrophy (thinning), striae (lines on the skin), and miliaria (rash due to blocking of the sweat glands, 'prickly heat').
Adult and pediatric patients (n = 347) with atopic dermatitis enrolled in three multicenter, randomized, 6-week studies who had previously used steroids were analyzed to examine the null hypothesis that improvement in atopic dermatitis initiated after prior treatment with steroids eliminates any subsequent treatment differences between tacrolimus ointment and pimecrolimus cream. Of these patients, 171 were randomized to tacrolimus ointment and 176 to pimecrolimus cream. Based on improvement in the Eczema Area and Severity Index at the end of study, tacrolimus ointment was significantly more effective than pimecrolimus cream (p = ). Tacrolimus ointment was also significantly more effective than pimecrolimus cream at the end of study in all secondary end-points. Overall, the frequency of adverse events was comparable between treatment groups (% for tacrolimus ointment vs. % for pimecrolimus cream). Tacrolimus ointment is more effective, with a similar safety profile, compared with pimecrolimus cream in patients with atopic dermatitis previously treated with topical corticosteroids.