Painful nodules covering scalp

A 48 year old man presents with a 2 year history of painful, disseminated, tender nodules covering his scalp. Many lesions are inflammatory with purulent discharge, and alopecia is noted over nodules. The patient reports clinical worsening after mental and physical stress. He has been treated with oral antibiotics, such as clindamycin hydrochloride and erythromycin, with poor response.