Response of alopecia areata to DNCB: influence of auto-antibodies and route of sensitization.

The effects of treatment with topical 2,4-dinitrochlorobenzene (DNCB) were observed in fifty-one patients with alopecia areata of at least 9 months duration. Patients were sensitized either by the application of 500 micrograms of DNCB in acetone to the forearm, or by painting affected areas of the left side of the scalp with a 1% solution. A mild to moderate dermatitis was maintained by weekly applications of DNCB. When the sensitizing dose was applied directly to the scalp, significantly more patients showed poor reactivity as judged by the eczematous response obtained, although the two routes of sensitization had comparable effects upon regrowth of hair. Hair regrew significantly more frequently in females. The likelihood of regrowth was reduced in patients with hair loss of long duration and in those with immunological disturbances such as autoantibodies or low T lymphocyte numbers and responses. The relationship of these factors to the disease and to the response to DNCB treatment is discussed.