lupus pernio

Lupus pernio (Latin 'frostbitten wolf') reflects non-caseating granulomatous infiltration of the dermis and is a marker of chronic, often refractory sarcoidosis with extracutaneous involvement, particularly upper respiratory tract sarcoidosis (nasal mucosa, sinuses, larynx) and pulmonary fibrosis. Histology shows the classic sarcoid 'naked' non-caseating granulomas (epithelioid histiocytes and Langhans giant cells with sparse surrounding lymphocytes), sometimes containing Schaumann bodies (calcified concentric inclusions) or asteroid bodies (stellate inclusions). Lupus pernio responds poorly to topical therapy and often requires systemic corticosteroids, methotrexate, or anti-TNF agents (infliximab, adalimumab). Other sarcoid skin findings: erythema nodosum (a feature of Löfgren syndrome — acute sarcoidosis with bilateral hilar lymphadenopathy, polyarthritis, and erythema nodosum — which carries a good prognosis, unlike lupus pernio).