Author and Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, February 2015.
Lupus erythematosus (LE) is a group of diverse, persistent inflammatory autoimmune diseases and often affects the skin. Discoid lupus erythematosus (DLE) is the most common chronic form of cutaneous lupus. It is characterised by persistent scaly, disk-like plaques on scalp, face and ears that may cause pigmentary changes, scarring and hair loss.
Factors leading to DLE include:
The manifestations of DLE are due to loss of regulation of the immune system in the skin.
DLE can affect males and females of any age. DLE is five times more common in females than males, and onset is most often between the ages of 20 and 40 years. DLE is more common than systemic lupus erythematosus (SLE). The estimated prevalence is around 20–40 people in every 100,000.
DLE may be more common in patients with darker coloured skin than in fair Caucasians.
Most patients with DLE just have skin involvement (cutaneous LE). Between 5% and 25% of patients with DLE develop SLE, in which there may be other forms of cutaneous lupus, and other organs may develop the disease. Typically, systemic symptoms are mild in these patients.
DLE may be localised (above neck in 80%) or generalised (above and below the neck in 20%).
Signs of localised DLE include:
Signs of generalised DLE include:
The patient's main concern is the unsightly appearance of the plaques, but they may also be itchy or sore.
DLE is often diagnosed from its distribution in sun-exposed sites and the clinical appearance of the plaques. After a careful history, the patient with DLE should undergo a thorough general examination, to find out if other forms of lupus may be present.
The diagnosis is usually confirmed by skin biopsy, in which typical features of lupus are noted: interface and periadnexal dermatitis, follicular plugging, atrophy and scarring. Direct immunofluorescence is often positive in lesional skin in DLE (positive lupus band test).
The Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) was developed in an attempt to classify the severity of cutaneous LE.  A score of activity and damage due to the disease is calculated in each of 12 anatomical locations (refer to the original published paper for details).
Total activity score is made up of:
Total damage score is made up of:
Patients with DLE will usually have blood tests at the time of diagnosis and from time to time afterwards.
Circulating autoantibodies are found in about 50% of patients with DLE.
About 25% of patients with discoid lupus erythematosus also develop systemic lupus erythematosus within months to decades of the diagnosis of skin disease.
Discoid lupus erythematosus may leave permanent scars, even when the active disease has responded to treatment.
The following measures are important to reduce the chance of flares of DLE.
Intermittent courses of potent topical corticosteroids are the main treatment for DLE. They should be applied accurately to the skin lesions for several weeks. Potency should be selected to suit the body site and thickness of the plaque. Very potent topical steroids may cause thinning of the surrounding skin and increase blood vessel formation (telangiectasia). Intralesional injections of corticosteroids are sometimes used, especially for hypertrophic DLE.
Camouflage makeup is useful to improve appearance.
Typically, any of the following drugs may be used to treat DLE alone or in combination. Treatment is less effective in smokers than in non-smokers.
DLE tends to persist for years or decades. In some patients, all signs of active disease resolve in time.
Squamous cell carcinoma can rarely arise within a longstanding DLE plaque in the skin or mucous membrane. It presents as an enlarging warty growth or ulcer. It is usually treated surgically.
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