Scalp sores, bumps or blisters may be caused by folliculitis, impetigo, contact dermatitis, viral infections or skin conditions, such as acne, according to eMedicineHealth. Sebaceous or epidermal cysts and skin cancer may also eventually lead to sores on the scalp.
Sores on the scalp can be caused by infection of the skin, which is known as impetigo, or infection of the hair shaft, which is known as folliculitis. Sores may also arise due to an allergic reaction in the skin caused by contact dermatitis or viral skin infections, such as shingles and chickenpox. Acne can cause sores on the scalp as well. Cysts that are caused by plugged ducts in the hair shaft can become sores on the scalp.
Ringworm is a fungal infection that commonly causes scalp sores, especially among children, explains HowStuffWorks. It leaves round patches on the scalp that are often swollen and red. These patches also sometimes cause hair loss or smaller black dots to occur on the scalp.
In areas of the scalp that are not well-covered by hair, skin cancer can destroy tissues and cells and may appear as a sore that does not heal. This includes both squamous cell skin cancer, melanoma or basal cell skin cancer.
Pemphigus, an immune system disease, causes itchy sores on the face and scalp, as HowStuffWorks explains. It is uncommon and generally affects older adults. Anyone with pemphigus should seek treatment from a dermatologist, because the condition is potentially dangerous.
Psoriasis is an immune system disease that also causes itchy sores on the scalp, notes HowStuffWorks. It causes cells to turn over much faster than they should, leading to immature skin cells accumulating and causing itchy sores.
Treatment for sores on the scalp is dependent upon the cause of the sores. Some sores may heal on their own while those that take a long time to heal may require evaluation by a medical professional.