Periungual and subungual pyogenic granuloma.

BACKGROUND: Nail pyogenic granuloma (PG) is common, often seen as an urgent case, given the recent onset as a bleeding nodule. Nail PGs are due to different causes that act through different pathogenetic mechanisms and may be treated in several ways. Both causes and treatments of nail PG have never been classified.

OBJECTIVES: To classify nail PG according to the pathogenesis, describe the clinical and pathological features and provide guidelines for a correct diagnosis and treatment.

METHODS: A retrospective, observational study was performed reviewing epidemiological and clinical features of 58 cases of PG seen at our Departments in the last 5 years. A review of the literature was also carried out, using PubMed database and dermatological textbooks.

RESULTS: Nail PG is usually due to the following causes: drugs, local trauma and peripheral nerve injury. Histopathology shows similar features in every type of PG, irrespective of cause and location.

CONCLUSIONS: The localization of nail PG, the number of digits involved and clinical history help to identify the cause. When PG is single, especially if it involves the nail bed, histological examination is necessary to rule out malignant melanoma. Treatment must be chosen according to the underlying cause.