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Seborrheic Keratosis ✅
Related Subjects: |Seborrheic Keratosis |Keratoacanthoma |Keloids
Epidemiology
- Rare in individuals under 30: Uncommon in younger people.
- Incidence increases with age: More frequent in adults over 40.
- Genetic factors: Often follows an autosomal dominant inheritance; multiple lesions may run in families.
🩺 Clinical Features
- Characteristic appearance: Well-defined, waxy papules or plaques with a "stuck-on" look.
- Variation in presentation: Color (light tan → black), size (small → several cm), shape (round/oval), may become warty, greasy, pigmented over time.
- Common sites: Face, trunk, upper extremities; palms and soles typically spared.
Pathophysiology
- Benign epithelial tumour: Arises from basal keratinocytes in the epidermis; non-cancerous.
- Growth pattern: Abnormal proliferation → raised lesions on the skin surface.
Differential Diagnosis
- Malignant melanoma: Lentigo maligna or nodular melanoma; requires urgent evaluation.
- Melanocytic nevi: Benign moles; irregular borders or color may mimic seborrheic keratosis.
- Pigmented basal cell carcinoma: Irregular borders, different growth pattern.
- Solar lentigo: Flat age spots with uniform pigmentation.
- Actinic keratosis: Sun-damaged, spreading pigmented lesions; pre-malignant.
🔎 Investigations
- Clinical diagnosis: Usually sufficient based on appearance and history.
- Biopsy: If diagnosis uncertain or malignancy suspected; differentiates from melanoma or BCC.
- Dermatoscopy: Useful for detailed lesion evaluation when clinical diagnosis is unclear.
💊 Management
- Observation: Asymptomatic, non-cancerous lesions with no cosmetic concern can be left alone.
- Liquid nitrogen cryotherapy: Quick freezing off lesions; temporary redness or swelling may occur.
- Curettage: Scraping off raised lesions under local anesthesia; ideal for thicker lesions.
- Electrosurgery: Excise difficult or resistant lesions using electrical current.
- Laser therapy: Less invasive option for larger or stubborn lesions.
- Topical treatments: 5-fluorouracil or imiquimod rarely used; more common in actinic keratosis.
📚 References
- Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 7th edition. Elsevier, 2020.
- James WD, Berger TG, Elston DM. Andrews' Diseases of the Skin: Clinical Dermatology. 14th edition. Elsevier, 2020.
- NHS.uk. Skin lesions and rashes: Seborrheic keratosis. View NHS page
- DermNet NZ. Seborrheic keratosis. View DermNet NZ page