Based on the patient's history and clinical features typical of an AIPD
[3] , to demonstrate the presence of hypersensitivity to progesterone, we performed patch testing, prick and intradermoreactions with progesterone solubilized in sesame oil as described
[2,3] .All these investigations were performed during the follicular phase to avoid interference with endogenous progesterone. While patch and prick testing remained negative, intradermoreaction with micronized progesterone (at a concentration of 50 mg/ml diluted at 1/10 and 1/100 in sesame oil) elicited both an immediate and delayed reaction.
The test at the 1/10 dilution triggered a very intense immediate reaction at the site of testing with a pruritic plaque of 6 cm in diameter associated with diffuse lesions (delayed reaction) on the trunk reproducing the usual relapsing dermatosis.