Dermatofibroma and halo dermatitis.

The occurrence of a halo of dermatitis surrounding acquired naevi was initially reported by Meyerson in 1971 with histological features of focal spongiosis, parakeratosis, irregular acanthosis and a lymphocytic infiltrate in the upper dermis. When the same inflammatory reaction occurs around other lesions it is referred to as the Meyerson phenomenon or halo dermatitis. We report a rare case of the Meyerson phenomenon occurring around a dermatofibroma in a 69-year-old woman. This case highlights that the phenomenon may occur in a broad range of clinical scenarios and is not limited to acquired naevi in young adults.