Letter: Treatment of atopic dermatitis with topically applied caffeine.

To the Editor.— Locally applied B-adrenergic agents suppress the immediate skin test reaction in atopic patients, presumably by increasing skin levels of cyclic adenosine monophosphate. 1 Caffeine, a methylxanthine, increases cyclic adenosine monophosphate by inhibiting cyclic nucleotide phosphodiesterase, the enzyme that degrades cyclic adenosine monophosphate. It seemed to us that using topical caffeine to increase skin levels of cyclic adenosine monophosphate might lessen the symptoms of atopic dermatitis. Patients with the typical flexural crease manifestations of atopic dermatitis were selected. The purpose of the study was explained to all patients, and written consent was obtained. Each patient was instructed to apply a cream labeled "R" to the right-sided lesions three times a day and at night, and to apply a cream labeled "L" to the left-sided lesions three times a day and at night. One side was treated with caffeine, 10%, in hydrophilic base, and the other side