Redness and swelling of the head may be caused by trauma, angioneurotic edema, herpes zoster and cellulitis. 1. Trauma: If the head is stimulated by external extrusion, collision, friction and other factors, it will lead to rupture of subcutaneous blood vessels in the head, poor blood circulation and redness. 2. Angioneurotic edema: generally related to heredity, mental state and other factors, will damage the deep skin of the scalp, so that the skin tissue is thickened, swollen, red, and accompanied by a burning sensation. 3. Herpes zoster: herpes zoster is related to immune factors, genetic factors, mental factors, viral infections and other reasons, the initial manifestation of pain, the later head can appear red spots, blisters. In severe cases, it can also cause redness and swelling of the scalp, accompanied by pain. 4. Cellulitis: Cellulitis is mostly caused by hemolytic streptococcus and staphylococcus aureus infections, which can be manifested as redness, swelling, pain and burning sensation in the affected area. If the symptoms of redness and swelling of the head appear, you should go to the hospital for timely examination and symptomatic treatment.