Five nearly identical cases of deep atrophy of the skin overlying the humeral insertion of the deltoid muscle presented a problem in diagnosis. Gowers' local panatrophy, atrophoderma of Pasini and Pierini, insulin lipodystrophy, postpanniculitis atrophy, partial lipodystrophy, and macular atrophy were considered unlikely to be the proper diagnosis. Atrophy at the site of injected corticosteroid was considered the most likely cause and the appearance of the lesions and the clinical course strongly supported this idea. Injections must be considered a likely cause of transitory atrophy in this site even when the patient's history and the physician's account do not support the idea. In any case, the area of the humeral insertion of the deltoid muscle is a poor one for intramuscular injections because there is little underlying muscle.
Fritsch WC. Deep Atrophy of the Skin of the Deltoid Area. Arch Dermatol. 1970;101(5):585-587. doi:10.1001/archderm.1970.04000050089012