Hand swelling and itching are usually caused by venomous insect bites, skin diseases and varicose veins of the upper extremities. 1. Venomous insect bites: when venomous insects like ants, spiders and lice bite the skin of the hands, they inject venom into the subcutaneous area, causing a localized allergic reaction, which, in the presence of the immune factor histamine, can lead to localized swelling and itching of the skin. 2. Skin diseases: allergic skin diseases including urticaria, eczema and contact dermatitis occurring on the hands can cause vasodilatation of the skin and mucous membranes of the hands and increased vascular permeability, which can lead to swelling and itching of the hands. 3. Upper extremity varicose veins: If the superficial blood vessels of the hand due to blood stagnation and tortuous, dilated, i.e., varicose veins of the upper extremities, can make the local skin due to lack of nutrients and the emergence of chronic ulcerative lesions, thus causing hand swelling, itching. Hand swelling and itching may have other reasons, to go to the regular hospital in time to identify the cause of the disease, and under the guidance of a professional doctor to choose a suitable method of treatment, do not blindly deal with their own.