Causes of red bumps on fingers include ringworm, scabies, erythema nodosum and urticaria. 1. Ringworm: Because the hands are infected by fungi, these fungi can cause erythema and pimples with itching after damaging the skin. 2. Scabies: when the fingers are infected by scabies, these scabies can damage the dermis, which can trigger the swelling of subcutaneous tissues, and red bumps can also appear. 3. Erythema nodosum: Inflammation of the intervals of the subcutaneous fat lobules due to a variety of factors, at which time the inflammatory factor causes swelling of the tissues and eventually a red rash. 4. Urticaria: it can be triggered by various factors such as allergy, infection, etc. At this time, histamine is released in large quantities, and the symptoms of red spots and air masses appear locally. The appearance of red bumps on the finger phenomenon, please consult a doctor in a timely manner, to clarify the cause of the disease, follow the doctor’s instructions for treatment.