Changes
/* Types of Alopecia areata */
[[image: Types of alopecia areate.jpeg|500 px|center|thumb]]
----
==Molecular Mechanism==
Alopecia areata is an autoimmune disease in which cells of the anagen hair bulb are attacked by T lymphocytes. In a process resembling chemotherapy-induced hair loss, lymphocyte infiltration of the growing hair bulb forces the anagen follicles into dystrophic catagen, causing the hair shaft to break off. Possible targets of autoimmune attack in alopecia areata include matrix keratinocytes, dermal papilla cells, and melanocytes. Linkage analyses indicate that this disease has a genetic component, though the range of associated genes, including the major histocompatibility complex, cytokine and immunoglobulin genes.
----
