Sweat blister, also known as dysphagic eczema, is a blistering disease of the palms and plantar areas of the feet. The disease mostly occurs in late spring and early summer, and can be self-healing in the winter when it worsens in summer. It is mostly seen in adolescents. The etiology is not fully understood. In the past, it was thought to be due to excessive sweating of the hands and feet and retention of sweat in the skin, but now it is mostly thought to be a non-specific eczema-like reaction of the skin. Systemic allergy to metals such as nickel and chromium and psychological factors may be an important cause of this disease. Clinical manifestations It usually begins in late spring and early summer, worsens in summer, and resolves spontaneously in winter, often coexisting with excessive sweating of the hands and feet, and recurs periodically each year. The lesions are usually found on the palms of the hands, the ends of the fingers, the sides of the fingers, and rarely on the backs of the hands and the soles of the feet, and often occur symmetrically. The typical lesion is a small, rice-grain sized, hemispherical blister located deep in the epidermis, slightly above the skin surface, without inflammatory reaction, scattered or clustered on the palms of the hands, flanks of the fingers and fingertips, and rarely on the back of the hands and soles of the feet, and often symmetrically distributed. The blisters contain clarified plasma and generally do not rupture on their own, and dry up to form peeling skin, revealing red new epithelium, thin and tender, which is often painful at this time. The surrounding skin is normal. The disease has varying degrees of pruritus and burning sensation. Diagnosis is easy based on seasonal recurrent attacks, symmetrical occurrence on the palms of the hands, damage is mostly small blisters, and peeling after drying. The patch test often does not help the diagnosis. Treatment 1.Oral medicine Short-term oral prednisone effect is good, for those who have mental tension can be appropriate sedative tranquilizer. 2.Topical medicine In the early stage, dryness and anti-itching are the main factors, and 1% phenol glycopyrrolate lotion can be applied externally; glucocorticoid cream or ointment can be used at the beginning of peeling; for those with repeated local peeling and dryness and pain, 2%~5% salicylic acid ointment and allantoin ointment can be used externally.