Unexplained itchy finger joints may be caused by frostbite, contact dermatitis, insect bite dermatitis, and other factors such as ringworm. 1. Frostbite: Frostbite is considered to be caused by prolonged and repeated exposure to cold or wet environment. If the patient has frostbite in the joint area of the fingers, the localization will show purple-red patches, itching, blisters, swelling and other manifestations. 2. Contact dermatitis: contact dermatitis may be caused by skin contact with exogenous substances such as animal fur, pollen and chemical agents. Patients will have skin erythema, edema, itching, burning, swelling and pain. 3. Insect bite dermatitis: Insect bite dermatitis is considered to be related to insect bites such as mosquitoes and mites. The affected area will have symptoms such as small blisters, red wind-bubble-like damage, itching, and pimples. 4. Other factors: patients with tinea cruris, trauma, eczema and other lesions on the finger joints may also have the manifestation of itchy fingers for no reason. There are many reasons for itchy finger joints, and it is recommended that patients seek medical treatment in time to clarify the causes and give treatment under the guidance of doctors.