Hair Development, Growth, and Loss 64 seen in 5–10% of patients (Figure 12). Nail changes, especially nail pitting, as well as a history of atopy, vitiligo, autoimmune thyroiditis, and other autoimmune diseases have been described in association with AA.87,88 The pathogenesis of AA remains incompletely understood, but it is generally regarded as an autoimmune process, and active melanocytes residing in the anagen hair follicles are one of the proposed targets of autoimmunity.87 The course of AA is unpredictable and a remittent and fluctuating course is not uncommon.87 Spontaneous resolution of hair loss is usually expected in patients with mild AA. The prognosis is generally poor in patients with higher disease severity and longer disease duration.89 There is thus far no definite treatment that yields sustainable effectiveness the use of corticosteroids either topically or systemically is the current mainstay treatment. Trichotillomania: Trichotillomania is a psychological disorder that refers to uncontrollable self-pulling or plucking of one’s hair leading to noticeable hair loss. It affects different age groups with different underlying mechanisms.90 Trichotillomania typically manifests as patchy hair loss in a bizarre shape with ill-defined borders (Figure 13). The remaining hairs over the affected area show uneven length. The course of the disease is usually benign and self-limited in children. In adults or the elderly, the behavior of hair pulling is often associated with underlying psychiatric disturbance.80,90 Treatment consisting of behavioral and pharmacological Figure 13. Trichotillomania An area of hair loss with an irregular border and broken hairs in uneven length on the top of the scalp