Periungual Pyogenic Granuloma-Like Lesions During Isotretinoin Treatment for Acne: Two Case Reports and a Literature Review

Periungual pyogenic granuloma-like lesions are not uncommon side effects of isotretinoin therapy, but these cases are relatively infrequently reported. Excessive granulation tissue appeared in two patients receiving oral isotretinoin therapy for severe acne. Once isotretinoin was discontinued, the outgrowths resolved spontaneously in both patients. It is probably an idiosyncratic reaction to isotretinoin which renders the skin more susceptible to extracellular matrix and blood vessel formation. Moreover, similar lesions may be observed particularly with newer targeted therapies, such as inhibitors of epidermal growth factor receptor (EGFR) and mitogen-activated protein kinase kinases (MEKs). EGFR inhibitors associated painful periungual inflammation (paronychia), which often arises from the nail wall during newer targeted therapies, has been classified in the third major group of dermatologic toxicity. Cutaneous toxicity may be interpreted as a stress response that affects epidermal homeostasis. In the cell, stress signals are transmitted to effectors which then produce an inflammatory response.

In conclusion, paronychia and excessive granulation tissue in the nail folds are not uncommon side effects of oral retinoids. It is therefore particularly important for practicing dermatologists to be aware that the best management approach is drug discontinuation.