Scalp Lesions: What That Bump or Sore on Your Scalp Could Be

Common causes of scalp lesions

Folliculitis

Folliculitis is inflammation of hair follicles, usually from bacteria (often Staphylococcus aureus) or yeast. Small itchy or sore pimples cluster on the scalp, sometimes leaving scabs. Sweating, hats, oily hair products and scratching make it worse. A rarer chronic form causes scarring hair loss.

Cysts and benign growths

• Pilar cysts: about 90 percent of these cysts occur on the scalp. They are smooth, dome-shaped and slow-growing. They can be removed if bothersome or inflamed.
• Seborrheic keratoses: common benign growths that look stuck on, ranging from tan to black. They can itch and catch on combs.
• Lipomas and nevus sebaceous (a yellow-orange, hairless patch present from birth) are other benign lesions.

Inflammatory skin conditions

• Psoriasis: well-defined red plaques with silvery scale, often extending past the hairline.
• Seborrheic dermatitis and eczema: scaly, itchy patches; scratching creates sores and scabs.
• Lichen planopilaris and discoid lupus: rare, cause scarring patches with permanent hair loss and need a dermatologist.

Infections and infestations

• Tinea capitis (scalp ringworm): scaly patches with broken hairs in children; sometimes a painful, boggy swelling called a kerion.
• Impetigo: honey-colored crusts, often after scratching.
• Shingles: painful blisters in a band on one side of the head; involvement near the eye needs urgent care.
• Head lice: intense itching with scratch marks and small red bumps at the nape of the neck and behind the ears.

Skin cancer on the scalp

The scalp is one of the most sun-exposed areas of the body, especially in men with thinning hair. Scalp skin cancers are often found late because they are hard to see.

• Actinic keratoses: rough, scaly spots that can turn into squamous cell carcinoma; easy to treat.
• Basal cell carcinoma: a pearly or shiny bump with tiny blood vessels, or a sore that bleeds, scabs, heals partly and reopens.
• Squamous cell carcinoma: a firm, scaly or crusted lump that grows over weeks to months, sometimes tender.
• Melanoma: scalp melanomas tend to be diagnosed later and can be more aggressive. Use the ABCDE rule: Asymmetry, Border irregularity, Color variation, Diameter over 6 mm, Evolving.

Ask your hairdresser or partner to tell you if they notice a new or changing spot.

How doctors diagnose scalp lesions

A primary care doctor or dermatologist will part the hair and examine the lesion, often with a dermatoscope (a lighted magnifier). Depending on the findings:

• skin scraping or hair sample for fungal culture
• swab for bacteria or viruses
• biopsy: a small sample taken under local anesthetic to confirm or rule out cancer or scarring conditions
• ultrasound for deeper lumps

Treatment

• Folliculitis: antibacterial or antifungal washes, topical antibiotics, and avoiding occlusive hats and heavy oils.
• Cysts: removal by minor surgery if bothersome; antibiotics if infected.
• Seborrheic keratoses: no treatment needed; freezing or removal if irritated.
• Psoriasis and seborrheic dermatitis: medicated shampoos, steroid solutions, and other prescription treatments.
• Ringworm: oral antifungal medicine for several weeks.
• Actinic keratoses: freezing, creams or photodynamic therapy.
• Skin cancers: surgical removal, often Mohs surgery for scalp cancers to spare tissue.

Protecting your scalp

• Wear a wide-brimmed hat outdoors.
• Use a spray or powder sunscreen of SPF 30 or higher on a bald or thinning scalp and along the part line.
• Avoid scratching, and treat itch early.
• Check your scalp regularly, or ask someone to help.

Frequently asked questions

What are the most common lesions on the scalp?

The most common are folliculitis (red bumps around hairs), pilar cysts, seborrheic keratoses, psoriasis and scabs from scratching itchy scalp conditions. In older adults with thinning hair, sun-related spots such as actinic keratoses and skin cancers become more common.

Why do I have scabs on my scalp that won't heal?

Persistent scabs often come from scratching psoriasis, eczema or folliculitis. But a sore that bleeds, scabs and reopens for more than 4 weeks can be a basal cell or squamous cell carcinoma. Have it checked by a doctor, who may take a small biopsy.

What does skin cancer on the scalp look like?

It may look like a pearly or shiny bump, a scaly, crusted lump, a sore that will not heal, or a dark spot that is irregular or changing. Bald or thinning areas are most at risk. Any new, growing or bleeding spot should be examined.

What is a hard bump on the scalp?

A smooth, firm, round bump that moves under the skin is often a pilar cyst, which is benign. Other causes include lipomas, bone growths (osteomas) and, less often, skin cancers. A lump that grows quickly, is fixed or painful should be checked.

Are scalp sores contagious?

Some are. Impetigo, scalp ringworm, head lice and shingles blisters can spread to others. Psoriasis, seborrheic dermatitis, cysts and skin cancers are not contagious. A doctor can tell the difference and recommend treatment.