Hair Loss: Common Causes and Treatment

T. Grant Phillips, MD; W. Paul Slomiany, MD; Robert Allison, DO

Disclosures

Am Fam Physician. 2017;96(6):371-378. 

In This Article

Approach to the Patient With Nonscarring Alopecia

The history and physical examination are often sufficient to determine a specific etiology for hair loss. It is convenient to divide the various causes into focal (patchy) and diffuse etiologies, and proceed accordingly. Patchy hair loss is often due to alopecia areata, tinea capitis, and trichotillomania. Diffuse hair loss is commonly due to telogen or anagen effluvium. Androgenetic alopecia may be diffuse or in a specific pattern, and may progress to complete baldness.

History

Important clues to the etiology of different patterns and types of hair loss are listed in Table 1 and Table 2. Hair that comes out in clumps suggests telogen effluvium. Systemic symptoms such as fatigue and weight gain suggest hypothyroidism, whereas a febrile illness, stressful event, or recent pregnancy may account for the diffuse hair loss of telogen effluvium. The use of hair products such as straightening agents or certain shampoos suggests a diagnosis of trichorrhexis nodosa. A family history of hypothyroidism may warrant laboratory testing for this condition, whereas a family history of hair loss supports the diagnosis of androgenetic alopecia.

Physical Examination

The physical examination should focus on the hair and scalp, but attention should be given to physical signs of any comorbid disease indicated by the review of systems. If only the scalp is involved, the physician should look for typical male or female pattern to determine the presence of androgenetic alopecia. Whole body hair loss is consistent with alopecia totalis. Dry, broken hair suggests trichorrhexis nodosa, whereas scaling, pustules, crusts, erosions, or erythema and local adenopathy suggest infection.

The pull test may be used to diagnose hair loss conditions.[1] The examiner grasps approximately 40 to 60 hairs at their base using the thumb, index, and middle fingers and applies gentle traction away from the scalp. A positive result is when more than 10% of hairs (four to six) are pulled from the scalp; this implies active hair shedding and suggests a diagnosis of telogen effluvium, anagen effluvium, or alopecia areata. However, a negative test result does not necessarily exclude those conditions. The pull test is difficult to standardize because the pulling force is not distributed uniformly and because it is difficult to approximate the number of hairs grasped, thereby leading to false interpretations.

Laboratory Studies

Because many conditions can cause hair loss, there are no routine tests to evaluate hair loss. Laboratory testing is indicated when the history or physical examination findings suggest an underlying comorbidity.

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