Hair loss and Alopecia Physical Examination and Testing
Once the history has been recorded, the patient should be examined. First look at the skin of the scalp. Note any erythema, scaling, or evidence of scarring. Areas of scarring can be skin colored, red or reddish-purple. These areas are often shiny and are devoid of hair follicles. Look for discrete areas of alopecia. Next, in a patient with non-scarring alopecia, measure the part widths. This is done by parting the hair in the occipital area and measuring how wide the part looks (not the distance between 2 hairs). Then do the same measurement at the posterior vertex, anterior vertex, and frontal crown areas.
The part width is a somewhat subjective measurement, however, if it is performed by the same observer over time, it is a useful tool. Examine the parietal areas and note the absence or presence of bitemporal or parietal thinning. Next, perform a pull test. This is accomplished by grasping a bunch of hairs and pulling lightly or by running your fingers through the patient’s hair. Alternatively, the patient can be directed to run her fingers through her hair.
The hairs that result from this maneuver are then counted. The test is performed in several areas over the scalp. The pull test is positive if at least 3 hairs are obtained with each pull or if more than 10 hairs total are obtained. The test may be falsely negative if the patient washed her hair just prior to the examination.
Additional areas to examine include the face (for excess facial hair, acne, or loss of eyebrows and eyelashes), the elbows and knees if psoriasis is suspected, the wrists, ankles, lower back and mouth if lichen planus/lichen planopilaris is suspected, the face, external ears and sun-exposed areas if discoid lupus is possible, and the pubic hair pattern if hyperandrogenism is suspected. If the clinician feels competent in examining the thyroid, this can also be performed.
Laboratory testing is directed by history and suspected diagnosis. This will be discussed for each specific diagnosis.