Swollen and itchy fingertips may be related to insect bite dermatitis, dactylitis, frostbite and other causes. 1. Insect bite dermatitis: when mosquitoes bite the skin of human fingers, they can release acidic substances into the body, which can produce an allergic reaction and symptoms of redness, swelling and itching of the fingertips. 2. Fingertipitis: a purulent disease that occurs in the fingertips, often secondary to onychomycosis, mostly manifested as redness and swelling of the fingertips, accompanied by itching and pain. 3. Frostbite: often occurs in cold winter, mainly manifested as purple-red patches on the skin, swelling, itching and blisters. It is recommended that people with swollen and itchy fingertips go to the hospital in a timely manner to clarify the cause of the disease and standardize the treatment under the guidance of the doctor, so as not to delay the condition of the body to bring about adverse effects.