Etretinate therapy of solar-related kerato acanthoma

Nineteen patients with a total of 22 keratoacanthomas were treated in this trial with 1 mgm/kg/day of etretinate for six weeks. The patients had predominantly solitary keratoacanthoma, all associated with severe solar damage. There was a provision for reduction of dose and also for extension of length of treatment time for lesions which had responded but had not completely disappeared at the end of six weeks. Sixteen of the nineteen patients cleared without recurrence. Two patients had therapy stopped because of side effects and in these, further treatment was required. These side effects were severe paronychia and elevation of serum lipids. Other side effects were almost exclusively muco-cutaneous. Keratoacanthomas on the head, neck and upper limbs had cleared completely at the end of six weeks therapy, with a variable degree of ridged scarring. Lesions on the lower legs almost invariably required treatment times which were longer than six weeks and could be up to twelve weeks. Etretinate therapy of solar related keratoacanthoma should be considered for large lesions, multiple lesions, lesions in areas which are difficult to treat, and lesions in patients unsuited for destructive therapy or surgery.