Scalp Bumps: Causes, Symptoms & When to See a Doctor

Scalp lumps are common and usually benign. Accurate diagnosis requires clinical evaluation; some need biopsy.

Common Causes by Category

Cystic / Follicular

• Pilar (trichilemmal) cyst: 90% on scalp; firm, mobile, keratin-filled; autosomal dominant.
• Epidermoid cyst: Central punctum; cheesy keratin.
• Folliculitis/deep folliculitis: Pustules, nodules; bacterial (S. aureus), fungal, or sterile.
• Hidradenitis suppurativa: Recurrent painful nodules, sinus tracts, scarring (occipital/nape).

Benign Tumors

• Lipoma: Soft, doughy, mobile, subcutaneous.
• Pilomatrixoma: Hard, calcified, "tent sign"; from hair matrix cells; child/young adult.
• Trichoepithelioma: Small, skin-colored papules; hair follicle origin.
• Dermatofibroma: Firm, dimple sign; often post-traumatic.

Inflammatory / Infectious

• Abscess/carbuncle: Fluctuant, erythematous, tender; needs I&D.
• Tinea capitis: Scaling, alopecia, black dots; fungal (Microsporum, Trichophyton).
• Dissecting cellulitis: Deep nodules, sinus tracts, scarring alopecia.

Trauma / Vascular

• Hematoma: Post-traumatic; fluctuant, ecchymosis.
• Aneurysm/arteriovenous malformation: Pulsatile, bruit.

Malignant

• Basal cell carcinoma: Pearly, telangiectatic, ulcerated; most common skin cancer.
• Squamous cell carcinoma: Keratotic, indurated; higher metastatic potential.
• Melanoma: ABCDE criteria; scalp melanomas have worse prognosis (delayed detection).
• Merkel cell, adnexal carcinomas, metastasis.

When to See a Doctor

• New lump >2 weeks
• Growing, changing color/shape
• Painful, ulcerated, bleeding
• Fixed to underlying tissue
• Associated lymphadenopathy
• History of skin cancer, immunosuppression

Diagnostic Steps

Dermoscopy → biopsy (punch, shave, excisional) → histopathology. Imaging if deep/large.

Most scalp bumps are benign, but scalp skin cancers are dangerous due to late detection. Regular scalp checks (hairdresser, partner, self) save lives.