These inciting factors can be organized into several categories, noted below. Scalp biopsy is the most useful test to confirm the diagnosis, although this is seldom necessary if the history is characteristic and a gentle hair pull produces numerous telogen hairs. Telogen hairs are identified by a white bulb and the lack of a gelatinous hair sheath. Chronic telogen effluvium may have a metabolic cause. Testing should be directed toward causes that are common and correctable.
Iron deficiency is common in premenopausal women.
Evaluation of CBC, serum iron, iron saturation, and ferritin may be warranted. Note that CBC results may be completely normal in women with mild iron deficiency and hair loss. Blood is more essential than hair, and the body will shed hair before red cell indices become microcytic. Also, note that ferritin behaves as an acute phase reactant. Inflammation can produce normal ferritin levels in an individual who is iron deficient.