The use of sensitizers to irritate the skin of the scalp and gain dermatitis has been well documented, including PUVA treatment, topical minoxidil and Cyclosporin A. Research is ongoing as no one thing proves to be the answer for all patients with A/A, A/T and AU.
alopecia areata, totalis and universalis
It is generally thought that both hereditary factors and a hypersensitivity to certain antigens influence a forecast of the probable course and outcome of alopecia areata but the triggering mechanisms remain, as yet, a mystery. However, recent research strongly supports the theory that T-lymphocytes as the causative agents are involved in the bringing about of AA, and maybe influence the duration of the alopecia A/T/U.
Unfortunately the development of A/A prior to puberty has a poorer outcome as it does for those with an atopic state 'a state of hypersensitivity to certain antigens'