Itchy armpits are related to physical factors such as clothing friction and heavy sweating, and also considered to be related to eczema, florid furuncle, psoriasis and so on. 1. Physiological factors: clothing friction, sweaty armpits caused by strenuous exercise, lack of attention to underarm hygiene, etc., may cause itchy armpits. 2. Eczema: the etiology of eczema is not clear, may be related to abnormal immune function, contact with allergens, chronic infectious lesions. Acute stage patients manifested as erythema, edema, millet size papules or herpes mound, subacute stage patients may have oozing skin, vesicles crust or flaking, chronic stage manifested as skin roughness and thickening, mossy lesions, etc., which can be manifested as itchy armpits. 3. maculopapular furuncle: maculopapular furuncle is caused by Malassezia infection, the patient lesions are characterized by pores as the center, the appearance of clearly defined punctate rash, adjacent lesions can be fused with each other to form an irregular sheet, and the surface is covered with fine scales; general patients have no self-awareness of the symptoms, but occasionally there is a mild sense of itching, so the disease will cause some patients with itchy armpits. 4. Psoriasis: the cause of psoriasis is not yet completely clear, may be related to genetic, environmental and other factors. Patients’ lesions are characterized by red papules or macules, red plaques, and covered with thick layers of silvery-white scales, which may have different degrees of itching symptoms. When patients have psoriasis in the armpits, the phenomenon of very itchy armpits can occur. It is recommended that people with itchy armpits use lukewarm water or local ice packs to relieve the itch, and if accompanied by other abnormalities, they should consult a doctor in a timely manner.