History
A 47-year-old woman is seen in the dermatology clinic with a 5-month history of itchy eruption consisting of lesions mainly on her feet but also scattered on her legs. The rest of her skin is unaffected. She does not complain of any symptoms in her mouth or involv-ing the genital area. On direct questioning she had noticed that some of her nails have become slightly brittle and are liable to splitting. No one else in the family is currently affected, although she thinks her mother had suffered with a similar skin eruption some years previously. She is otherwise well and not taking any regular medication.
Examination
There are multiple, discrete, purplish, shiny flat-topped papules over the dorsum of her feet; some of the lesions have a lacy white pattern over their surface (Fig. 27.1). Further similar lesions are seen scattered on her lower legs; some of the papules are clustered in a linear fashion demonstrating Koebner’s phenomenon. A number of her fingernails have longitudinal ridges on them with ‘V-shaped’ nicks. Her mouth, genital region and scalp are all normal.
Questions
• What is the diagnosis?
• What triggers are known to be associ-ated with this skin disease?
• What are the treatment options for this patient?
Medicine
This woman was diagnosed with cutaneous lichen planus. The aetiology of the eruption is unknown; however, it is thought to be an immunologically mediated disease and is known to be associated with autoimmune diseases and hepatitis C. Recent articles suggest that 16 per cent of patients with lichen planus have underlying hepatitis C. In addition numerous medications have been implicated in triggering lichenoid drug reactions including diuretics, -blockers, NSAIDs, angiotensin converting enzyme inhibitors, statins and tetracyclines. A familial tendency has been reported in association with certain human leucocyte (HLA) types being implicated including HLA-B7, HLA-DR1/10. Clinically lichen planus presents with an insidious onset, mildly to intensely pruritic eruptions especially seen on the flexor aspects of the wrists but also scattered on the limbs and trunk. The lesions themselves are usually papules that are purplish in colour, shiny and firm on palpation. There may be a fine white lacy pattern of scale on the surface of the lesions (Wickham’s striae). Lesions may form discrete nodules/plaques and become quite hyperkeratotic. A scarring alopecia can develop due to scalp involve-ment, so-called lichen planopilaris. In addition to the cutaneous eruption, patients may have involvement of the mouth and genital mucosae with sore erosions and ulceration. Nails changes may also feature and are characterized by longitudinal ridges and brittle ‘V-shaped’ nicks in the distal nail plate. The diagnosis is usually made on clinical grounds. However, histological features seen on a skin biopsy can be helpful in distinguishing between lichen planus and lichenoid drug eruptions when a drug trigger is suspected. Most lichen planus settles within months to years and responds well to potent topical steroids, phototherapy or short courses of oral prednisolone. Orogenital involvement, however, may be more persistent and recalcitrant and may require prolonged systemic immunosuppressant therapy such as mycophenolate mofetil.
KEY POINTS
• Lichen planus is an itchy papular eruption of insidious onset.
• In extensive or atypical disease think about a possible drug trigger or underlying hepatitis C.
• Cutaneous lesions respond to potent topical steroids but orogenital disease is more recalcitrant.
need an explanation for this answer? contact us directly to get an explanation for this answer