Hair bulb accumulation of Langerhans cells in allergic patch tests.

The occurrence of occupational allergic contact dermatitis due to 2,3-epoxypropyl trimethyl ammonium chloride (EPTMAC) is reported and supplemented with immunohistochemical and electron microscopic observations. Four young workers developed hand dermatitis at a factory in which modified, cationic starch is manufactured. EPTMAC, a quaternary ammonium compound used as a cationizing chemical in the process, produced allergic reactions in all four patients in epicutaneous testing. The patients had only been in contact with EPTMAC for a short time (one to three months) before developing allergic eczema, which indicates that EPTMAC is a strong sensitizer. Immunohistochemistry showed that dendritic OKT6+ cells (Langerhans cells) increase in the hair follicles and the peribulbar infiltrate during the allergic patch test indicating that hair follicles might actively be involved in delayed type allergic reactions, possibly as a shunt way for allergens. Using electron microscopy, mitotic immunocompetent cells were found in the epidermis during the allergic patch test.