Nickel contact allergy and menstrual cycle.

According to some reports in the literature, the hormonal fluctuations which occur during the menstrual cycle may affect the clinical expression of contact allergy to a greater or lesser degree. In clinical practice, too, patient history often shows exacerbation of the contact dermatitis during the days immediately preceding menstruation. On the contrary, the follicular phase of the cycle seems to have a temporary protective role in inhibiting the eliciting phase of allergic contact dermatitis. One possible explanation for this phenomenon is of immunological type: it has been demonstrated that oestradiol induces inhibition of delayed hypersensitivity type reactions, probably by acting indirectly on cells having a regulatory function in cell-mediated immunity. To investigate any inhibitory effect of the ovulatory phase of the menstrual cycle on contact sensitization, 30 selected fertile women, allergic to nickel sulfate and with a regular menstrual cycle lasting between 25 and 32 days, were enrolled. Patch tests were performed with a series of 10 serial aqueous dilutions of nickel sulfate, from 5% to 0.0013%. The 30 women were tested at 2 different times, in the ovulatory phase (demonstrated by transvaginal ultrasound) and the progestinic phase; they were subdivided into 2 groups of 15 women: in one group, the tests were made first in the ovulatory phase, and in the other, first in the progestinic phase of the menstrual cycle. There was a minimum interval of 5 weeks between the 2 test phases. The study shows that during ovulation the patch tests elicited significantly less intense responses than in the progestinic phase. These data therefore suggest that the ovulatory phase of the cycle has a significant inhibitory role on delayed hypersensitivity type reactions. For this reason, negative responses to patch tests executed in this phase could likely be false-negatives, and after careful evaluation of the phenomenon and of the clinical condition and patient history, it may be considered advisable to repeat the tests during the progestinic phase of the menstrual cycle.