Redness, swelling and pain in the armpits may be caused by diseases such as folliculitis and inflammation of the lymph nodes in the armpits, and it is recommended that the patient undergoes a timely examination and is treated with relevant medications under the guidance of the doctor. 1. Folliculitis: the cause of folliculitis is still unclear, and may be related to mite parasites, allergies and other factors. Folliculitis can stimulate hair follicles, leading to damage to the skin barrier, resulting in redness and swelling in the armpits, accompanied by pain. Patients can use mupirocin ointment, fusidic acid cream and other drugs for treatment. 2. Inflammation of axillary lymph nodes: usually due to inflammation and infection and other factors, the continuous stimulation of inflammatory mediators may cause the patient to develop axillary redness and swelling, accompanied by the phenomenon of pain. Patients can be treated with medications such as purging and dispersing tablets and roxithromycin. Redness, swelling and pain in the armpits may also be related to sebaceous cysts and other factors, it is recommended that the patient should go to the hospital in time for examination, after clarifying the cause of the disease can be taken under the guidance of the doctor for treatment.