A hair pull test should have normal values reduced to two hairs or fewer and the current 4- to 5-day restriction on hair washing and brushing also can be reduced, according to study results published in the Journal of the American Academy of Dermatology.
A hair pull test is used for monitoring advancing alopecia areata, acute cases of telogen effluvium, anagen effluvium and loose anagen syndrome, and if more than 10% of hairs in a pulled bundle are removed, the results are considered positive. The test is conducted at four locations on the scalp.
Researchers in Canada studied 182 volunteers (102 women; mean age, 26.95 years;), including medical students, who completed a questionnaire regarding demographics, medications and hair health and history. One person was excluded from analyses because of an active hair loss disorder.
Most patients were aged 25 years or younger (74%) with Caucasian textured hair (77%). There was a single hair pull test performed on a bundle of approximately 50 to 60 hairs of 4-6 mm in diameter at the vertex of the scalp.
There was a mean number of 0.44 hairs removed during the hair pull test (SD = 0.75, range 0-4).
Regardless of whether participants washed their hair the day of the test, the day before or more than 2 days before the test, there was no significant difference in mean number of hairs removed. Time since brushing, using the same time frame, also did not have an affect on mean of hairs removed.
Male and female participants did not have a significant difference in mean hairs removed. Caucasian-, Asian- and Afro-textured hair had similar hair pull test values.
Hair-pull values were not affected by medication use, with no significant difference in mean hairs removed between women taking oral contraceptive pills and those who did not.
Hair pull test values also were not influenced by tight hairstyles.
“This study has newly quantified the hair pull test (normal ≤ 2 hairs) using pretest guidelines that fit our societal norms,” the researchers concluded. “Hair brushing was examined as potential new factor to impact pretest guidelines. However, the results showed that neither hair brushing nor hair washing altered the hair pull test results. Hair washing and brushing may now occur at any time before the hair pull test instead of 4 to 5 days.
“Hair pull test on Caucasian-, Asian- and Afro-textured hair types were similar, but require future research.” – by Bruce Thiel
Disclosure: The researchers report no relevant financial disclosures.