Alterations of melatonin secretion in atopic eczema.

The circadian rhythm of melatonin secretion of the pineal gland can be disturbed in a variety of clinical conditions and diseases including some psychic disorders. To study the rhythmic behaviour of melatonin secretion in atopic eczema (AE), melatonin serum levels were measured every 2 h, starting at 8 a.m. in 18 patients suffering from severe AE. In 6 patients exhibiting low serum levels of melatonin, the circadian melatonin rhythm was found to be abolished. In 8 patients a diminished nocturnal melatonin increase was observed compared with the controls (n = 40). Only 4 patients showed a normal secretion pattern of melatonin. The results provide some evidence of a dysfunction of the pineal gland in AE, possibly due to a partially reduced activity of the sympathetic nervous system being involved in the control of melatonin secretion.