Discoid Lupus Erythematosus

Essentials

• Photosensitivity may be due to DLE.
• Diagnosis is based on clinical presentation and histological examination of a skin biopsy.
• Management consists of symptomatic treatment and prevention of exacerbations.
• The possibility of systemic lupus erythematosus (SLE) should be considered.
• Cutaneous manifestations are encountered in all main types of lupus disease: DLE, subacute cutaneous lupus erythematosus (SCLE) and SLE.

Definition, aetiology and epidemiology

• A chronic photosensitive autoimmune disease, which may cause permanent scarring on the skin
• Aetiology is unknown but hereditary factors play a part in disease appearance.
• More common in women, age of onset generally between 20 and 40 years

Disease types

• In lupus confined to the skin, other clinical subtypes have been described in addition to the most common discoid (DLE) type.
• DLE must be differentiated from SLE, which is associated with systemic symptoms.
• SCLE is a subtype of DLE with reddish and scaly lesions mainly on the upper body and mild systemic symptoms (pictures ).
• Overlapping is noted when only the cutaneous manifestations of lupus diseases are evaluated.
  • 10-20% of patients with SLE present with cutaneous symptoms suggestive of DLE.
  • 5-10% of patients with DLE may develop SLE with time.
• The different types of lupus diseases are distinguished with the aid of clinical presentation, systemic symptoms and laboratory investigations (antinuclear antibodies).

Clinical presentation

• Skin lesions are visible on areas exposed to the sun (face: pictures ; scalp: pictures ; neck, upper chest; backs of the hands, arms).
• DLE may have many clinical manifestations, and the course of the disease may be variable.
• Exacerbations are usually seen in the spring and summer.
• The typical plaques are clearly demarcated, the size of a finger tip, reddish and scaly; as they develop they may atrophy in the middle and scar the skin.
• The lesions are usually asymptomatic, but they may present with pruritus or tenderness.
• The lesions often develop 1-2 weeks after sunlight exposure.
• On the scalp, DLE may cause scarring alopecia (see Hair Loss and Balding), which may have significant aesthetic implications.
• Rarely causes ulceration in the oral mucosa (picture ).
• Some patients exhibit systemic symptoms, such as fatigue, myalgia, arthralgia, slight fever and laboratory tests may show abnormalities (see below).
  • In these cases, the symptomatology may overlap with that of SLE and other connective tissue disorders. The full criteria for SLE are usually not fulfilled.

Diagnosis

• Based on clinical presentation as well as histological and immunofluorescence tests of a skin biopsy
• Fungal samples (for culture and microbiology) of single lesions may be indicated to exclude tinea.
• SLE may produce similar skin lesions and must be excluded with the aid of patient history, physical examination and laboratory tests.
  • Full blood count, CRP, ESR
  • Creatinine, ALT, alkaline phosphatase
  • Urinalysis
  • Serum antinuclear antibody analysis, antibodies to extractable nuclear antigens, DNA antibodies
  • Plasma C3 and C4 complement levels
• Any systemic symptoms are investigated using appropriate laboratory tests and imaging techniques.
• The results may be positive for antinuclear antibodies (the ANA test is positive in 5-10% of patients) and show blood picture changes (leucocytopenia, thrombocytopenia) even in cases where the disease is confined to the skin.
• Typical autoantibody profiles may be seen in connective tissue disorders.
• Diagnosis can never be made based on antibody tests alone, and overlapping between the diseases occurs.
  • A positive test result for SSA antibodies and SSB antibodies (Sjögren's syndrome antibodies), may be suggestive of SCLE.
  • Positive test results for DNA antibodies, ribonucleoprotein antibodies and Smith (Sm) antibodies are suggestive of SLE.

Differential diagnosis

• Skin changes due to SLE Systemic Lupus Erythematosus (Sle) (discoid skin lesions, butterfly rash)
• Polymorphous light eruption: recurring, small pruritic papules on the chest and backs of the hands in the spring, appearance directly linked to the time elapsed from sun exposure
• Drug-induced photodermatitis and other photodermatitis Photodermatitis
• Rosacea Rosacea: papules and pustules, telangiectasia, lesions only on the face
• Psoriasis Psoriasis: typical sites of predilection, nail involvement
• Tinea Dermatomycoses: isolated lesions with scaling around the borders

Treatment Drugs for Discoid Lupus Erythematosus

• The treatment of general symptoms follows the guidelines given for SLE Systemic Lupus Erythematosus (Sle).
• Treatment aims to eliminate symptoms, control the active disease, prevent exacerbations, minimise drug adverse effects as well as to improve the quality of life.
• Active skin lesions require effective management in order to prevent scarring of the skin and consequent cosmetic issues.
• Avoidance of the sun's UV radiation by wearing correct clothing and using sun screens may prevent the development of new lesions.
• Less aggressive lesions can be treated with topical therapy.
  • An adequately long treatment period with moderately potent to potent glucocorticoid creams, for example once daily in the evening for 2-3 weeks, thereafter twice a week for 1-2 months as required.
  • Tacrolimus cream is also a good choice, for example twice daily until the rash has started to subside, thereafter twice a week as required.
• Systemic treatment
  • The first-line treatment is hydroxychloroquine. Regular laboratory monitoring is recommended during the treatment (full blood count, ALT) as well as check-ups by an ophthalmologist (before treatment if needed and then every 5 years).
  • Oral glucocorticoids may be considered as short term treatment in a severe exacerbation, for example prednisolone 30-40 mg in the mornings whilst tapering the dose down over 2-4 weeks.
  • Other treatment alternatives include immunosuppressive medication prescribed under the supervision of a dermatologist or rheumatologist (e.g. methotrexate, azathioprine, mycophenolate mofetil or dapsone, thalidomide or retinoids).

Specialist consultation and monitoring

• The diagnosis and treatment of DLE are the responsibility of a dermatologist.
• In mild disease forms, the monitoring may be carried out in primary health care.
• Treatment response may show great variation, and the disease may reactivate after many years of remission.
• If SLE is suspected, a referral to a specialist in internal medicine or a rheumatologist is required.

Pictures