Koebner phenomenon
Related Subjects:
|Nikolsky's sign
|Koebner phenomenon
|Erythema Multiforme
|Pyoderma gangrenosum
|Erythema Nodosum
|Dermatitis Herpetiformis
|Lichen Planus
|Acanthosis Nigricans
|Acne Rosacea
|Acne Vulgaris
|Alopecia
|Vitiligo
|Urticaria
|Basal Cell Carcinoma
|Malignant Melanoma
|Squamous Cell Carcinoma
|Mycosis Fungoides (Sezary Syndrome)
|Xeroderma pigmentosum
|Bullous Pemphigoid
|Pemphigus Vulgaris
|Seborrheic Dermatitis
|Pityriasis/Tinea versicolor infections
|Pityriasis rosea
|Scabies
|Dermatomyositis
|Toxic Epidermal Necrolysis
|Stevens-Johnson Syndrome
|Atopic Eczema/Atopic Dermatitis
|Psoriasis
🩹 The Koebner Phenomenon occurs when trauma to normal skin is followed by new lesions that are identical to those of the underlying skin disease. These lesions are clinically and histologically indistinguishable from the primary disease.
💡 Classic example: new psoriasis plaques forming along a scratch line.
📖 About
- Named after Heinrich Koebner (1838–1904), a 19th-century dermatologist.
- Refers to the appearance of lesions at sites of trauma (e.g. surgical scars, scratches, burns).
- Also called the isomorphic response.
🧾 Conditions Associated with Koebner Phenomenon
🧴 Psoriasis
- Red, scaly plaques on extensor surfaces (elbows, knees, scalp).
- New plaques form at sites of trauma.
- 💊 Tx: Topical steroids, vitamin D analogues, retinoids; systemic (methotrexate, ciclosporin, biologics); UV phototherapy.
💜 Lichen Planus
- Violaceous, flat-topped papules on wrists, forearms, legs.
- Wickham’s striae (fine white lines).
- Lesions appear after trauma/friction.
- 💊 Tx: Topical steroids; systemic corticosteroids or immunosuppressants if severe; retinoids or phototherapy for chronic disease.
⚪ Vitiligo
- Depigmented patches on hands, face, periorificial areas.
- New patches may appear at trauma sites.
- 💊 Tx: Topical steroids, calcineurin inhibitors; narrowband UVB phototherapy; depigmentation therapy in extensive disease.
⚪ Lichen Sclerosus
- White, atrophic plaques affecting genital/perianal regions.
- Associated with itching, soreness, pain.
- Koebnerisation may occur after trauma.
- 💊 Tx: High-potency topical steroids (e.g. clobetasol); tacrolimus if resistant.
🦠 Flat Warts (Verruca plana)
- Flat-topped, small papules on face, neck, hands.
- Spread along trauma lines (e.g. shaving).
- 💊 Tx: Topical salicylic acid, retinoids; cryotherapy or laser if resistant.
🌞 Cutaneous Lupus Erythematosus
- Erythematous, scaly plaques, worse in sun-exposed sites.
- Trauma can exacerbate lesion formation.
- Often photosensitive.
- 💊 Tx: Topical steroids or tacrolimus; systemic hydroxychloroquine, steroids, immunosuppressants if severe; sun protection essential.
📚 References
