Lichen simplex chronicus
Also called neurodermatitis, LSC
The itch-scratch cycle made solid: one or a few thickened, bark-like plaques sculpted by years of rubbing at reachable sites, nape, ankles, forearms, genitals. The skin is the record of the behaviour, and the behaviour is the treatment target.
How it looks
A solitary, well-demarcated, lichenified plaque with exaggerated skin markings and post-inflammatory hyperpigmentation on an easily reached site.
Rose is the lesion, grey the pattern the lesions make, green where on the body it lives.
Across skin tones
Lichenification is more prominent and hyperpigmented in deeply pigmented skin, and the plaques leave long-lasting pigment change; follicular prominence within the plaque is a common additional feature.
Symptoms & course
- Paroxysmal, compulsive itch, often worst at night or when idle
- Scratching feels intensely relieving, which sustains the cycle
Diagnostic approach
- Clinical diagnosis
- Biopsy only for atypia or treatment failure
- Consider patch testing when a contact allergen might be feeding the itch
Differential, and how to separate them
- Psoriasis
Favours it: A fixed well-demarcated scaly plaque
Against it: Psoriatic scale is silvery and the sites are extensor; LSC sits where a hand habitually reaches
- Atopic dermatitis
Favours it: Lichenified itchy plaques in an atopic patient
Against it: Atopic disease is symmetric and flexural; LSC is one or a few sculpted plaques, though it often grows out of atopy
- Lichen planus
Favours it: Pruritic violaceous thickened lesions
Against it: LP is polygonal, papular, Wickham-striated, and often mucosal; LSC is a single built-up plaque
Management principles
- Break the cycle: potent topical corticosteroids under occlusion
- Night-time antihistamines or behavioural strategies against unconscious scratching
- Treat any underlying dermatosis, xerosis, or neuropathy driving the itch
Clinical pearl: Ask the patient to show you how they scratch; the plaque sits exactly where their dominant hand lands, which is also why the mid-back is spared.
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