Boils on the top of the head are usually caused by bacterial infections, low immunity and lack of hygiene. 1. Bacterial infection: boils, also known as boils, are usually caused by bacterial infections, such as Staphylococcus aureus. When the pathogenic bacteria are infected, redness and swelling usually appear, leading to boils. 2. Low immunity: when the patient is in poor living habits and diet for a long time, the immunity may be lowered, so the resistance to external stimuli will be lowered, leading to the multiplication of bacteria that colonize the scalp follicles, thus leading to boils. 3. Failure to pay attention to hygiene: If the patient does not pay attention to the hygiene of the head for a long period of time, the bacteria may multiply and stay on the surface of the skin, thus resulting in boils. Patients are advised to go to the hospital for treatment and not to use drugs indiscriminately to avoid aggravation of the condition.