Hair loss of three or four strands with a gentle tug belongs to alopecia areata, which is generally considered to be physiological alopecia areata, not pathologic alopecia areata.
The growth cycle of hair is usually 3 years, the regression period is 3 weeks, the resting period is 3 months, and the daily hair loss is about 60 to 80 strands, not more than 100 strands at most.
Normal hair loss is in the degenerative and resting phase of the hair, due to enter the degenerative phase and the new hair into the growth phase of the hair is constantly in dynamic equilibrium, so it can maintain a normal number of hair, so shedding three or four hairs in the number of hair loss is not considered to be pathological hair loss.
If there are more than 100 hairs per day or patchy hair loss for more than 3 months, or hair thinning visible to the naked eye and positive hair pulling test, it can be called pathological alopecia. Hair falling off with a gentle tug will lose three or four strands of hair is not pathologic alopecia.
Hair gently pulled off three or four hair usually does not belong to the pathology, such as hair loss increase, it is recommended to go to the regular hospital for endocrine and other related examinations to further clarify.