Lichen Simplex Chronicus

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Lichen Simplex Chronicus: Definition - The Itch That Rashes

  • Localized, well-circumscribed area of chronic lichenification (thickened skin, exaggerated skin markings).
  • Develops due to an "itch-scratch-itch" cycle: chronic, repetitive scratching or rubbing.
  • Often termed "the itch that rashes" as pruritus (itching) precedes the skin changes.
  • Not a primary skin disease.

⭐ LSC is a secondary skin disorder, not primary; it results from chronic physical trauma (rubbing/scratching) to the skin.

LSC on dark skin

Lichen Simplex Chronicus: Pathophysiology - Skin's Vicious Loop

LSC is driven by a vicious cycle: an initial itchy stimulus provokes scratching, which traumatizes the skin. This trauma induces epidermal changes that paradoxically intensify the itch, perpetuating the cycle.

⭐ The itch-scratch-itch cycle is central to LSC, leading to epidermal hyperplasia (acanthosis), hyperkeratosis, and nerve fiber proliferation.

Lichen Simplex Chronicus: Clinical Features - Skin's Thick Story

  • Intense Pruritus: Hallmark; paroxysmal, worse at night (itch-scratch cycle).
  • Characteristic Lesions:
    • Well-demarcated, thickened (lichenified) plaques.
    • Exaggerated skin lines (Lichenification).
    • Hyperpigmentation (post-inflammatory); may be hypopigmented in darker skin.
    • Dry, leathery, "cobblestone" texture.
    • Excoriations, fissures.
  • Common Sites (accessible to scratching):
    • Nape of neck, scalp.
    • Ankles, lower legs.
    • Wrists, extensor forearms.
    • Anogenital area. Lichen Simplex Chronicus Plaque

⭐ Key morphological features include well-demarcated, lichenified plaques with exaggerated skin markings and intense pruritus, often worse at night or during periods of rest.

Lichen Simplex Chronicus: Diagnosis & DDx - Not Just Any Itch

  • Clinical Diagnosis:
    • History: Intense, chronic, localized pruritus; habitual scratching.
    • Morphology: Well-demarcated, lichenified plaques; exaggerated skin markings, excoriations, hyperpigmentation.
  • Biopsy: Confirmatory; differentiates from key DDx.
  • Differential Diagnosis (DDx):
    • Psoriasis, Chronic Atopic Dermatitis, Nummular Eczema
    • Tinea Cruris/Corporis (fungal)
    • Allergic Contact Dermatitis
    • Squamous Cell Carcinoma (SCC) in situ (Bowen's disease)

⭐ Diagnosis is primarily clinical based on history and morphology; biopsy (showing acanthosis, hyperkeratosis, papillomatosis, and chronic inflammation) is confirmatory and helps rule out differentials like psoriasis or fungal infections.

Lichen Simplex Chronicus: Management - Calming the Chaos

  • Strategy: Interrupt itch-scratch cycle; reduce inflammation & lichenification.
  • Key Pharmacotherapy:
    • First-line: Potent topical corticosteroids (e.g., clobetasol propionate 0.05%).
    • Refractory: Intralesional triamcinolone acetonide (2.5-10 mg/mL).
    • Pruritus: Sedating antihistamines (e.g., hydroxyzine) for nocturnal relief.
  • Essential Adjuncts: Behavioral modification (stop scratching!), occlusive dressings.

⭐ Management cornerstones: breaking the itch-scratch cycle (behavioral modification, occlusive dressings) and potent topical corticosteroids (e.g., clobetasol propionate). Intralesional steroids for refractory lesions.

High‑Yield Points - ⚡ Biggest Takeaways

  • Localized neurodermatitis resulting from chronic, repetitive scratching/rubbing.
  • Hallmark: Lichenification (thickened skin, exaggerated skin lines, leathery texture).
  • Intense, paroxysmal pruritus is characteristic, often initiating the itch-scratch cycle.
  • Common locations: nape of neck, ankles, wrists, extensor forearms, anogenital area.
  • Skin shows hyperpigmentation and excoriations.
  • Histopathology: epidermal hyperplasia (acanthosis), hyperkeratosis, chronic dermal inflammation.
  • Treatment aims to break the itch-scratch cycle using potent topical corticosteroids and occlusion.

Practice Questions: Lichen Simplex Chronicus

Test your understanding with these related questions

A 70-year-old man comes to the emergency department because of a skin rash and severe itching. He appears ill; there is a generalized skin rash that is scaly, erythematous, and thickened. His palms, soles, and scalp are also involved. Which of the following is the most likely diagnosis?

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Flashcards: Lichen Simplex Chronicus

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_____ eczema presents as an eruption that is typically oedematous, vesicular and may be exudative.

TAP TO REVEAL ANSWER

_____ eczema presents as an eruption that is typically oedematous, vesicular and may be exudative.

Acute (Acute/Chronic)

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