chronic lichen simplex

• Synonyms: Vidal’s circumscribed neurodermatitis; “lichen simplex chronicus (LSC)”. Historically described as Vidal’s neurodermatitis in the late 19th century; reported in English by Adamson in 1910. [show_150ms_ease-in] » data-testid=»webpage-citation-pill»> pmc.ncbi.nlm.nih.gov

• Epidemiology: Adults (peak 30–60 years), slight female predominance; true prevalence unknown; frequently associated with atopic dermatitis (AD) , anxiety/depression, and sleep dysfunction. It commonly affects areas easily accessible for scratching (nape of the neck, neck, ankles, forearms, scalp, anogenital region). [show_150ms_ease-in] » data-testid=»webpage-citation-pill»> pmc.ncbi.nlm.nih.gov +1

• Pathophysiology (summary): Localized pruritus perpetuated by an itch-scratch cycle , epidermal hyperplasia and papillary dermal fibrosis , with cutaneous hyperinnervation and neuroimmune dysfunction (e.g., IL-31, neuropeptides). [show_150ms_ease-in] » data-testid=»webpage-citation-pill»> pmc.ncbi.nlm.nih.gov

• Codes: ICD-10: L28.0 (Lichen simplex chronicus). ICD-11: group EA83.0 Lichen simplex (includes vulva, male genitalia, perianal, etc.).

• Diagnostic checklist (quick)

☐ Well-defined, lichenified, pruritic plaque in an accessible area.

☐ Look for triggers (DA, contact, stress, dysesthesia).

☐ Consider KOH/scraping if tinea/scabies; patch test in chronic anogenital.

☐ If atypical/refractory: punch biopsy (4–6 mm) of thicker area.

☐ Plan: Powerful CST + occlusion + emollients + HRT/TCC ; assess calcineurin; safety follow-up.