actinic granuloma actinic granuloma actinic granuloma is a cutaneous condition characterized histologically by a dermal infiltrate of macrophages.: 706 actinic granulomaother nameso'brien granulomaspecialtydermatology actinic granuloma is an asymptomatic granulomatous reaction that affects sun-exposed skin, most commonly on the face, neck, and scalp. it is characterized by annular or polycyclic lesions that slowly expand centrifugally and have an erythematous elevated edge and a hypopigmented, atrophic center. advise to reduce exposure to the sun and to use sunscreen. treatment with topical halometasone cream, pimecrolimus cream.