There are many reasons for itchy armpit bumps, commonly caused by folliculitis, eczema, ringworm and other diseases. 1. Folliculitis: long-term moisture in the armpits can easily cause infection of the hair follicles, leading to folliculitis, resulting in itchy armpits and localized raised bumps. 2. Eczema: mainly due to abnormal immune function, allergens, microorganisms, environmental temperature or humidity changes and other external causes, as well as internal causes such as stress and anxiety, resulting in localized eczema in the armpits, itchy blisters, and ulcers, vesicles, and oozing and other symptoms may also occur. 3. Ringworm: Because the armpits are moist and sweaty, they are prone to fungal infections and itchy bumps. When the symptoms of itchy bumps appear in the armpit should go to the hospital, to clarify the cause of the disease, and follow the doctor’s instructions for treatment.