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Traumatic alopecias

Traumatic alopecias

Traumatic alopecias are caused by physical agents that act on the scalp, inducing hair loss of variable degree that range from transitory to permanent alopecia. This section will review those traumatic alopecias in which a biopsy may be useful to establish a diagnosis. These include trichotillomania, pressure alopecia, and traction alopecia.

An association has been found between psoriatic alopecia, alopecia areata, and Renbรถck phenomenon.9,10 Drugs that have been associated with psoriatic alopecia include methotrexate, hydroxyurea, retinoids, lithium, and carbamezapine11โ€“16 The use of tumor necrosis factor-alpha inhibitors, particularly infliximab and adalimumab, in patients with Crohn disease has also been linked with the disease.17,18