How to Diagnose Hair Loss

The document from January 1, 2013, provides a guide for clinicians on diagnosing hair loss, emphasizing the differentiation between hair loss from the roots and hair breakage. It outlines the hair follicle cycle, noting that 85% to 90% of scalp hair is in the anagen phase and grows about 0.35 mm per day, with normal hair loss ranging from 40 to 300 hairs per day. The authors recommend using a Hair Card for clinical examination, a scalp biopsy for suspected cicatricial alopecia, and taking a thorough medical history. Differential diagnoses for hair loss include telogen effluvium, alopecia areata, androgenetic alopecia, tinea capitis, and trichotillomania. Diagnostic methods include pull and tug tests, hair mount preparation for microscopic examination, and laboratory tests such as complete blood count and hormone levels. Scalp biopsies should be performed in areas with inflammation for cicatricial alopecia. These tools and tests are crucial for identifying the cause of hair loss and determining the correct treatment.