This article addresses the type of lupus erythematosus that is mainly confined to the skin (DLE). See also the article Systemic lupus erythematosus Systemic Lupus Erythematosus (Sle).
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 12).
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 34; scalp: pictures 56; 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 7).
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.
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 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.