Mechanism of action: Topical immunotherapy acts by varied mechanisms of action. The most important mechanism is a decrease in CD4 to CD8 lymphocyte ratio which changes from 4:1 to 1:1 after contact immunotherapy. A decrease in the intra-bulbar CD6 lymphocytes and Langerhan cells is also noted. Happle et al, proposed the concept of ‘antigenic competition’, where an allergic reaction generates suppressor T cells that non-specifically inhibit the autoimmune reaction against a hair follicle constituent. Expression of class I and III MHC molecules, which are normally increased in areas affected by alopecia areata disappear after topical immunotherapy treatment 34 .A ‘cytokine inhibitor’ theory has also been postulated 34 .
Up to 50 percent of women will experience female pattern hair loss during their lifetime. 1 Patients usually present with hair thinning over the central area of the scalp and widening of the midline part, but with reservation of the frontal hairline ( Figure 3 ). Women who also have abnormal menses, history of infertility, hirsutism, unresponsive cystic acne, virilization, or galactorrhea should have a targeted endocrine work-up for hyperandrogenism (., testosterone, dehydroepiandrosterone sulfate, and prolactin), although most will have normal androgen levels. 29 Evaluation for iron deficiency, thyroid disease, and syphilis (a rare cause) should be considered because they can contribute to hair thinning or generalized hair loss.