Red and itchy hands may be caused by contact dermatitis, mosquito bites and other reasons. 1. Contact dermatitis: hands in contact with hair dye, capsaicin, paint and other irritants or contact with pollen, skin care products and other allergic substances caused by perverse reactions, may induce contact dermatitis, resulting in redness and itching of the hands, and blisters may appear in severe cases. 2. Mosquito bites: Inflammatory reactions may occur after mosquito bites on the hands, resulting in localized redness and itching. Itchy red hands may also be seen in ringworm, urticaria and other causes, it is recommended that patients go to the hospital to improve the relevant examination, a clear diagnosis and treatment as prescribed by the doctor.