Sweat hair can not grow out usually have two conditions, the first case is the most common, is due to pore blockage, pore keratinization, also known as periportal keratosis or pore keratosis. The surface of the hair follicle can be observed with the naked eye to form small round particles, slightly harder to the touch than normal skin, picking off the surface of the small round particles of keratinized parts can be seen in the small particles of curly hair accumulation inside, can not grow out of the body normally, mainly due to genetic factors, if the impact is small can not be treated. The second situation is less common, that is, the patient’s other parts of the sweat hair has grown out, but no hair growth in the armpit, usually the patient can be found under the skin more black thick hair did not grow out normally, this situation is a normal phenomenon, at this time no special treatment, and wait for the hair to grow long, can grow out on their own. If the keratosis is obvious, you can use Adapalene gel or compound lactic acid cream to apply, which can make the keratinized hair follicle mouth return to normal within 5-10 days, while oral vitamin A and vitamin E can increase the efficacy, and topical salicylic acid ointment and cod liver oil ointment can be applied topically. However, it should be noted that the disease cannot be completely cured, and keratinized pores will form again after stopping the medication for some time.