Alopecia Areata is a systemic autoimmune disorder where autoantibodies are driven against anagen hair follicle.
Pathogenesis and genetics
Its thought to be systemic autoimmune disorder affecting anagen hairfollicle.Its T-cell mediated inflamatory non scarring condition. T-cell mediates inflamatory response around hair follicle which damages hair follicle.
Endogenous retinoids metabolic disorder plays a major role in its pathogenesis.
Atleast 129 various SNP are associated with this disease in genome.
Atleast 4 regions in genome are found to have these genes
Genes associated with this disease have functions of controlling the activation and proliferation of regulatory T cells, cytotoxic T-Lymphocyte-Associated Antigen 4, InterLeukin-2, InterLeukin-2 receptor A, and Eos, and HLA.
PRDX5 and STX17 genes expressed in the hair follicle are associated with Alopecia Areata.
It shares genetic risk with autoimmune conditions like Diabetes Mellitus Type 1, Rheumatoid Arthritis and may accompany each other.It may be the only manifestation of Celiac disease.
Cases with congenital Alopecia Areata are also noted.It has strong hereditary association.Its a non contagious disease.
Symptoms and classification
It presents itself with small well demarcated bald patches with seemingly healthy skin below, with no scarring on skin. It can affect any region that has hair but it usually involves , scalp and beard. The patches are usually circular but it can present in any shape and extent. The hairs on the border of bald patches are very easy to pluck off compared to other regions.
Diffuse Alopecia Areata the baldness is diffused over whole scalp rather than in patches.
Alopecia Monolocularis bald patch is located only in one spot
Alopecia Areata Multilocularis many bald spots
Ophiasis hairloss at margins of hairline in waveforms
Alopecia Areata Barbae disease is limited only in beard region
Alopecia Areata Totalis complete hairloss of scalp
Alopecia Areata universalis all hair of each and every region are lost.
Trichoscopy shows evenly distributed hyperkeratotic plugs called yellow plugs, small shoots of hairs like exclamation marks , and destroyed hair follicles in follicular openings called black dots.