[Kyrle's disease (hyperketarosis follicularis et parafollicularis): local and systemic therapy with vitamin A acid (retinoic acid)].

The cause of Kyrle's disease (hyperkeratosis follicularis et parafollicularis) is unknown. The prognosis is very poor indeed; there is no specific treatment. The normal ranges of serum retinol and carotene were investigated in 10 healthy females. In a female patient suffering from Kyrle's disease, the serum level of retinol was found in the lower part of the normal range. Striking improvement has been noted when the patient was treated systemically with vitamin A acid (retinoic acid) which was associated with elevation of serum levels of retinol and carotene. When this form of therapy was withdrawn, recurrence of the skin lesions was observed and the serum levels of retinol and carotene declined to a level similar to that before the treatment. The administration of vitamin A acid was resumed, and with rising levels of retinol and carotene the skin condition again improved. Several possibilities regarding the treatment of Kyrle's disease as well as the mode of action of vitamin A acid are discussed.