Skin can provide a vital clue to diagnosis of internal disease. Exfoliative dermatitis (erythroderma) is an uncommon potentially serious inflammatory skin disorder characterized by an intense, widespread erythema and variable scaling. It results from aggravation of pre-existing skin disease, or may be caused by drugs or neoplasms. Although various paraneoplastic dermatoses may occur in association with carcinoma lung, erythroderma as the sole presenting feature is infrequently reported in literature. Herein we describe an elderly male in whom recalcitrant erythroderma led to the diagnosis of squamous cell carcinoma lung with fatal outcome.