Papulosquamous diseases of the scalp, such as psoriasis and seborrheic dermatitis, can produce telogen effluvium. Chronic telogen effluvium is hair shedding lasting longer than 6 months. The onset is often insidious, and it can be difficult to identify an inciting event. Because of the duration of the hair shedding, patients are more likely to complain of decreased scalp hair density, or they may note that their hair appears thin and lifeless. The physical examination is the same in both acute and chronic telogen effluvium.
Physical findings are sparse.
Usually, the physician does not appreciate a decrease in hair density. However, if the patient's hair has been falling out for several months, the hair may appear thin when compared with old photographs. Depending on the duration of hair loss, close examination of the scalp may reveal a higher than expected number of short new hairs growing. Because hair grows at a nearly constant rate of approximately 1 cm per month, the duration of the hair shedding can be estimated by measuring the length of the short hairs. In active telogen effluvium, the gentle hair pull test will yield at least 4 hairs with each pull.