Diffuse alopecia areata is a unique type of alopecia areata that involves widespread scalp hair thinning, instead of just the characteristic patches seen in the normal variant of AA . It is a non-scarring alopecia and can be difficult to diagnose in patients. Although the exact pathophysiology of AA is unknown, it is believed that it has an autoimmune mechanism that targets anagen stage follicles, causing disruption of hair fiber growth. The immune system could be attacking hair follicle melanocytes, dermal papilla cells, and keratinocytes, but as of yet this has not been well established. Diffuse AA is often characterized by more intense inflammation and faster progression compared to patchy AA. The inflammatory infiltrate in diffuse AA includes mononuclear cells, eosinophils, CD3+ T cells, and CD8+ T cells .
KeywordsAnagen phase Melanocytes Dermal papilla cells Keratinocytes Inflammation Mononuclear cells Eosinophils CD3+ T cells CD8+ T cells Female preponderance T cells Anagen phase Pruritus Scalp dysesthesias Biopsy Follicular edema Cellular necrosis Pigment incontinence Microvesiculation Telogen effluvium Androgenic alopecia Dermoscopy Topical immunotherapy Dinitrochlorobenzene (DNCB) Squaric acid dibutyl ester Diphencyprone (DPCP) Severe dermatitis