The penis root pubic hair grows a small red bud may be related to folliculitis, sebaceous cysts, warts and other reasons, should be clear in time the specific cause. 1. Folliculitis: due to the penis root hair is relatively lush, men wear underwear is too tight, not breathable, and long-term in a high temperature environment, may lead to hair follicle infection, caused by folliculitis, due to the inflammation stimulation may make the local appearance of red buds and other symptoms. 2. sebaceous cysts: oil secretion or more skin dirt, may lead to localized sebaceous cysts in the scrotum, resulting in the root of the penis in the hair grow a red buds, and in severe cases, there will be ulceration, pus and so on. 3. Warts: mainly due to sexual contact with the human papilloma virus infection, may make the glans localized white or red spots, cauliflower-shaped, the area may gradually increase, may also appear on the penis root pubic hair to grow a small red buds and other symptoms. This symptom alone is not enough to diagnose the disease, and may be caused by other factors. It is recommended that the patient consult a doctor in time to clarify the cause of the disease and give targeted treatment.