A teenage boy presents with closed comedones and slightly tender erythematous papules and pustules on his forehead, cheeks, chin, chest, and upper back. Small lesions developed several years ago as he entered puberty, and they have progressively worsened over the last year. Previous lesions have left residual red-brown hyperpigmentation.
Acne conglobata is severe, nodulocystic acne without associated systemic manifestations.  Acne fulminans is the most severe form of cystic acne, characterised by the acute onset of nodular and suppurative acne associated with multiple systemic manifestations, including fever, arthralgias, myalgias, hepatosplenomegaly, and osteolytic bone lesions.  Acne mechanica is caused by persistent mechanical obstruction, often by clothing or sporting equipment, which occludes the pilosebaceous unit and results in comedones.  Acne excoriee des jeunes filles typically occurs in girls who scratch and pick at comedones and inflammatory papules. Acneiform eruptions can be caused by some medicines (e.g., androgens, topical corticosteroids, oral corticosteroids) and occupational or environmental exposures (e.g., chloracne caused by dioxins).