Abstract Topical use of immune response modifiers, such as imiquimod, has increased in dermatology. Although its topical use is well tolerated, it may be associated with exacerbations of generalized cutaneous inflammatory diseases, possibly through the systemic circulation of pro-inflammatory cytokines. This report describes a case of development of pityriasis rubra pilaris, a rare erythematous-papulosquamous dermatosis, in a woman aged 60 years during treatment with imiquimod 5% cream for actinic keratosis. It evolved with erythrodermic conditions and palmoplantar keratoderma, presenting progressive clinical resolution after the introduction of methotrexate. The authors emphasize the importance of recognizing possible systemic reactions associated with the topical use of imiquimod.

Acne fulminans is a rare and serious condition characterized by the sudden onset of nodular and ulcerative acne lesions associated with systemic symptoms. It has been recognized a subset of patients with a sudden worsening of acne, often during treatment with oral isotretinoin, but without the strong presence of systemic involvement. Recognized by some authors as "pseudo-acne fulminans" or " acne fulminans sine fulminans," we report a case with these features in order to draw attention to the recognition and early management of this manifestation.