Lumps in armpits may be caused by enlarged lymph nodes, sebaceous cysts, paronychia and other factors. 1. Enlarged lymph nodes: the lymph nodes around the armpits are very rich, inflammation, tumors and other factors may cause the lymph nodes in the armpits to be enlarged, resulting in bumps in the armpits. 2. Sebaceous cysts: . If the sebaceous glands and sebum secreted in the armpits cannot be discharged from the follicular opening in time, they may accumulate in the glands and form cysts, which may lead to the appearance of bumps in the armpits. 3. Paratesticular glands: generally caused by congenital developmental abnormalities, mainly occurring in the armpit area, clinical symptoms manifested as localized elevated lumps, which may be accompanied by mild pain. The armpit lumps should be examined in a timely manner in the hospital, after clarifying the cause of the disease, under the advice of a professional doctor, choose the appropriate treatment, so as not to delay the condition.