Clinical and histopathological features of itch in patients with alopecia areata.

Alopecia areata (AA) is commonly characterized by patchy areas of hair loss on the scalp. AA has been considered as a tissue-specific and T cell-mediated autoimmune disease of the hair follicles with a genetic predisposition to hair loss (1, 2). Patients with AA sometimes report experiencing itch on the scalp at the same time as an increase in hair loss activity. However, the relationship between the mechanism of itch and hair loss in patients with AA is unclear. We report here clinical and histopathological features of patients with itchy AA, focussing on mast cells and the expression of 5-lipoxy-genase (5-LOX), a key enzyme for the production of the itch mediator leukotriene B 4 (LTB 4). ResuLTs A total of 156 patients with AA (92 females and 64 males , age range 4–80 years) attending our clinic between August 2009 and April 2011 were enrolled in this study. The subtypes of AA were as follows: 34 simplex (22%), 64 multiplex (41%), 39 totalis (25%), 9 universalis (6%), 8 ophiasis (5%), and 2 acute diffuse and total alopecia of the female scalp (ADTAFs) (1%). Out of these 156 patients with AA, 14 (11 females and 3 males, 11–68 years) reported experiencing itch, represented by tickling or an ant-like crawling sensation, on the lesion at the same time as the increase in hair loss, when the hair was lost suddenly. The patients with itch were diagnosed as 5 AA multiplex (36%), 5 totalis (36%), 2 ophiasis (14%) and 2 ADTAFs (14%). In 12 out of 14 patients with AA with itch, the intensity of itch was decreased in tandem with the decrease in hair loss. In the histopathological study of the scalp, we compared 2 AA patients with itch (male 72 years; female 43 years) with 2 normal subjects (male 40 years; female 37 years) and 2 patients with androgenetic alopecia (AGA) without itch (males 43 and 32 years). We were not able to obtain skin tissues from patients with AA without itch. Compared with normal subjects and patients with AGA, epidermal thinning and massive lymphocytic infiltration around the hair follicles were shown in the lesional skins of patients with AA and itch (Fig. 1). Toluidine blue staining of skin sections showed a high number of both total and degranulated mast cells around the hair follicles and hair bulbs in patients with AA (Table I). 5-LOX was highly expressed in epidermis and around …