Whereas acne and hirsutism represent the results of stimulation of the PSU, alopecia, or the loss of hair, may represent the reverse process. Paradoxically, alopecia may also be related to hyperandrogenism.128,129

Alopecia usually occurs with various other disease states. Among these are systemic diseases such as systemic lupus erythematosus, dermatomyositis, and lymphomas. Endogenous or exogenous hypercortisolism, hyperthyroidism and hypothyroidism may be accompanied by alopecia. Near-complete alopecia may develop in early infancy in patients with severe hereditary resistance to 1,25-dihydroxyvitamin D. Severe febrile episodes may cause hair loss within 3 months, and alopecia may result from chemotherapy and radiation therapy. Infections of the hair follicles and scalp may also cause hair loss.


Alopecia areata causes single or multiple round, bald patches on the scalp, which may be self-limiting and may respond to local corticosteroid treatment. This form of alopecia is thought to be autoimmune, with >40% of patients having antimicrosomal antibodies. Thyroid disease may coexist in this group; no androgen abnormality appears to be present.


The most common form of alopecia is male-pattern baldness, called “alopecia androgenica.” This process, which may be extremely gradual, occurs to some extent in virtually all men and many women, but in different patterns. In women, the frontal fringe remains intact130 (Fig. 101-20). The characteristic abnormality is a gradual transition from terminal to vellus hair (see Fig. 101-6). However, frankly male-pattern baldness may also occur in women. This pattern is associated with significant elevations in circulating androgens, such as are observed when ovarian tumors are present. Two different types of androgen-related hair loss are found in women. The first and most common type is not usually associated with an increase in androgen production. The second is associated with increased androgen production and may coexist with other virilizing features (see Fig. 101-20).

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Aug 29, 2016 | Posted by in ENDOCRINOLOGY | Comments Off on ALOPECIA

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