Pimples on the scalp are fairly common but they are painful as well as annoying. There are several causes for pimples on the scalp. Some of these causes include: contact dermatitis caused by allergic reaction on the skin; seborrheic dermatitis fed by excessive scalp oils; viral infection such as shingles or chickenpox; folliculitis which is an infection of the hair shaft; impetigo an infection of the skin; and epidermal or sebaceous cysts. Pimples most often develop when the follicle of... more »