There are various reasons for fingernail pain and redness and swelling, and the common causes are: inguinitis, local trauma, purulent dactylitis and so on. 1. Inguinitis: this disease is related to bacterial infection, long-term contact with irritants and other factors, after the onset of the tissue around the fingernail will be red, become swollen, painful, and even pus, skin and nail plate separation and other symptoms, generally speaking, acute inguinitis is slightly heavier than chronic inguinitis in terms of redness, swelling and pain. 2. Local trauma: when the fingernail is accidentally hit by a heavy object or caught in a door panel, redness, swelling, pain and other phenomena may also occur. 3. Purulent phalangitis: when the skin around the fingernail is purulent infection of the subcutaneous tissue due to stabbing, scratching or biting, redness, mild to moderate swelling, and pinprick-like pain may also occur. As the condition progresses, the pain will become stronger and stronger, and it may even cause skin necrosis and fever. When you find fingernail pain and redness and swelling, you should go to the regular hospital in time to find the cause and cooperate with the doctor to actively treat it.