Experiments were carried out in an elderly lady with fixed drug eruption (phenolphthalein). Negative results were obtained to patch and intradermal testing, skin perfusion techniques, and an in vitro challenge system. For the first time in the literature, we were able to show that cooled stored serum taken from the height of an attack and injected intradermally will produce a local inflammatory response. The serum factor responsible is a thermolabile substance.
Wyatt E, Greaves M, Søndergaard J. Fixed Drug Eruption (Phenolphthalein)Evidence for a Blood-Borne Mediator. Arch Dermatol. 1972;106(5):671-673. doi:10.1001/archderm.1972.01620140019006