Causes of scalp sores include fungal infections, bacterial infections, clogged hair shafts, acne and viral infections, according to HowStuffWorks. Scalp sores are also caused by AIDS, HIV, pemphigus, psoriasis and inherited skin disorders.
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.
A bacterial infection that causes scalp sores is impetigo, which is initially caused by cuts in the skin, according to HowStuffWorks. Bacteria enter through the cuts and infect the scalp. Prevent impetigo by washing any cuts on the scalp with an antibacterial soap and clean water.
Clogged hair shafts cause both scalp sores and scalp cysts, which should be treated by a dermatologist, states HowStuffWorks.
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.