A patient exhibited a fixed allergic reaction to penicillin and reacted to tests with two penicillin antigens only at the site of the clinical reaction. This site was one of a preexisting chronic superficial fungous infection.
Dennison WL, Clendenning WE. Fixed Eruption Due to Penicillin Allergy. Arch Dermatol. 1970;101(5):594-597. doi:10.1001/archderm.1970.04000050098015