Erythema ab igne appears as brown to red, reticulated, macular patches on areas of skin repeatedly exposed to heat. We found an increased amount of elastic tissue in the upper corium in lesions located on the buttocks of two patients. The elastic tissue was best demonstrated with use of cryostat sections stained with aldehyde-fuchsin. Sections of adjacent uninvolved skin were used for controls. The possible contributing role of sunlight in the production of elastosis in pretibial lesions of erythema ab igne previously reported is ruled out in these patients with lesions of the buttocks.
Johnson WC, Butterworth T. Erythema ab Igne Elastosis. Arch Dermatol. 1971;104(2):128-131. doi:10.1001/archderm.1971.04000200016004