Retinoid therapy is associated with excess granulation tissue responses.

In our clinical trials of isotretinoin therapy for cystic acne and etretinate treatment of psoriasis, eight patients had growth of excessive granulation tissue. The granulation tissue was found in resolving acne lesions in one patient taking isotretinoin. Among the psoriatic patients taking etretinate, the granulation tissue usually was seen adjacent to nail plates. In two patients, the side effect caused them to stop retinoid therapy. The tissue response did not appear to be related to the daily or cumulative retinoid dose.