This report of three cases of dermatitis repens is presented because of the rapid and striking therapeutic results obtained in each case with 10% Peruvian balsam in petrolatum after many previous attempts at therapy had failed. The entity of dermatitis repens is rather poorly defined. Its differential diagnosis includes acrodermatitis continua of Hallopeau, pustular psoriasis, acrodermatitis pustulosa perstans of Sachs, and pustular bacterid of Andrews. The clinical, histological, and pathological features which are said to distinguish these conditions are equivocal. We have diagnosed dermatitis repens here because the cases fitted Radcliffe-Croker's original description1 well. REPORT OF CASES Case 1.—T. W., a 53-year-old white machinist, first noted a small horny growth on the fifth digit of the left foot six months prior to admission to our clinic. In fingering the lesion, the patient had pulled off the "growth," leaving an open sore, which then slowly spread peripherally despite various