Squamous cell carcinoma complicating prurigo nodularis.

Squamous cell carcinoma complicating ulcerative prurigo nodularis is described in 2 patients who were having prurigo nodularis on dorsum of the feet for duration of many years. Biopsy specimens from the ulcerating nodules showed features of squamous cell carcinoma. This finding has not been previously reported. Squamous cell carcinoma should be considered in the evaluation of long standing ulcerative lesion of prurigo nodularis especially when not responding to conventional therapy.