Infection can develop after an injury or wound to the skin, a bite or sting, a tattoo or piercing, or other skin problem. Symptoms of infection may include:

• Increased pain, swelling, redness, or warmth around the affected area.
• Red streaks extending from the affected area.
• Drainage of pus from the area.
• Swollen lymph nodes in the neck.
• Fever.

Scratching an itchy scalp can lead to skin irritation or infection. Examples of infections that may affect the scalp include:

• Infection of the hair shafts (folliculitis), which begins as a red, tender area at or near the base of one or more strands of hair. Folliculitis may look like small red pimples with a hair in the center of each one. The pimples may have pus in them, and they often itch or burn.
• A bacterial skin infection, such as impetigo or cellulitis.

Chemicals in dyes, tints, bleaches, straighteners, and permanent waves as well as in soaps, shampoos, and perfumes may irritate the skin, causing contact dermatitis, or an allergic reaction.

Certain diseases may increase your risk of a serious infection. People with diabetes or an impaired immune system may require medical treatment at the first symptoms of infection.

Although many scalp infections get better by themselves, treatment with medicine may be needed.