OVERVIEW

What is cutaneous lupus erythematosus?

Lupus erythematosus is an autoimmune disease related to dysfunction of the immune system, which can affect various parts and organs of the body.

Lupus erythematosus typically has an insidious onset and is difficult to detect. However, once an acute episode occurs, the condition can become severe. After an acute episode, the disease does not resolve completely but tends to recur persistently, with symptoms appearing unpredictably, much like the cunning nature of a wolf.

When lupus erythematosus primarily affects the skin, it is referred to as "cutaneous lupus erythematosus" (CLE). When it involves multiple systems and organs throughout the body, it is called "systemic lupus erythematosus" (SLE).

Click to learn more about "systemic lupus erythematosus."

Cutaneous lupus erythematosus has many subtypes, each with different manifestations and varying treatment approaches. With proper treatment, skin lesions can often resolve.

What is the relationship between cutaneous lupus erythematosus and systemic lupus erythematosus?

Cutaneous lupus erythematosus (CLE) can occur as a manifestation of systemic lupus erythematosus (SLE) or independently of SLE.

SLE is often accompanied by CLE, and approximately 80% of SLE patients develop CLE at some point during the course of the disease. However, CLE frequently occurs independently of SLE, and most CLE patients do not have SLE.

The prevalence of CLE may be 2–3 times higher than that of SLE.

SYMPTOMS

What are the clinical manifestations of cutaneous lupus erythematosus?

Cutaneous lupus erythematosus can be classified into lupus-specific and lupus-nonspecific skin lesions based on morphology and histopathology.

Lupus-specific skin lesions include:

• Acute cutaneous lupus erythematosus (ACLE): localized and generalized types.

• Subacute cutaneous lupus erythematosus (SCLE): drug-induced and neonatal types.

• Chronic cutaneous lupus erythematosus (CCLE): discoid lupus erythematosus (DLE), verrucous lupus erythematosus (vLE), tumid lupus erythematosus (TLE), lupus erythematosus profundus (LEP), chilblain lupus erythematosus (CHLE), etc.

Lupus-nonspecific skin lesions include photosensitivity, diffuse or localized non-scarring alopecia, Raynaud's phenomenon, nail fold capillary dilation and erythema, vasculitis (especially vasculitis-like lesions on the extremities), livedo reticularis, acrocyanosis, atrophie blanche, and other skin lesions.

What are the common clinical manifestations of cutaneous lupus erythematosus?

1. Acute cutaneous lupus erythematosus:

• Localized type: Typically presents as characteristic localized facial rashes, also known as malar rash or butterfly rash, featuring erythema distributed on the cheeks and bridge of the nose. The nasolabial folds are usually spared. The erythema may last for hours, days, or weeks and often recurs, especially after sun exposure.

• Generalized type: Mainly manifests as red maculopapular rashes in sun-exposed areas. The extensor surfaces of the arms and hands are commonly affected, while the skin over the knuckles is usually spared.

2. Subacute cutaneous lupus erythematosus: Initially appears as small, slightly scaly red papules, which may later develop into psoriasiform plaques (papulosquamous SCLE) or annular plaques (annular SCLE). The latter often merge to form polycyclic or varied patterns. The plaques are typically red with varying degrees of scaling. The most commonly affected areas are sun-exposed regions, including the shoulders, forearms, neck, and upper trunk. Although sunlight exacerbates the condition, the face is often spared.

3. Chronic cutaneous lupus erythematosus: Discoid lupus erythematosus is the most common type.

• Discoid lupus erythematosus: Characteristic lesions are discrete, red, indurated plaques covered with well-defined adherent scales that extend into dilated hair follicles (follicular plugging). These plaques tend to expand slowly, with active inflammation at the periphery, and may eventually heal, leaving central depressed scars, atrophy, telangiectasia, and hyperpigmentation and/or hypopigmentation. The face, neck, and scalp are most frequently affected.

• Other types: Less common and not discussed in detail here.

CAUSES

What are the possible causes of cutaneous lupus erythematosus?

• Genetic factors: Cutaneous lupus erythematosus tends to run in families, indicating a genetic predisposition. Among twins, identical twins have a much higher chance of developing the condition simultaneously compared to fraternal twins.

• Sex hormones: Women are nine times more likely to develop systemic lupus erythematosus and three times more likely to develop cutaneous lupus erythematosus than men, suggesting that female hormones may influence the onset of the disease.

• Environmental factors such as UV radiation: UV exposure can trigger or worsen the condition. This may be related to UV-induced damage to keratinocytes, DNA alterations, the release of "hidden antigens," or the expression of new antigens, leading to the production of corresponding antibodies and immune complex-mediated damage.

• Medications and infections: Certain drugs, such as hydralazine, procainamide, methyldopa, isoniazid, and penicillin, as well as infections like streptococcus and Epstein-Barr virus, can induce or exacerbate the disease.

Who is more likely to develop cutaneous lupus erythematosus?

The condition is most common in women of childbearing age, typically between 15 and 55 years old.

Is cutaneous lupus erythematosus always caused by genetics?

Not necessarily. Many patients with cutaneous lupus erythematosus have no family history of the disease. Apart from genetic factors, the higher prevalence in women (nine times for systemic lupus and three times for cutaneous lupus) suggests a possible influence of female hormones. Certain medications can also induce drug-induced lupus, but in most cases, autoantibodies gradually disappear after discontinuing the drug, and patients recover. Drugs known to trigger SLE symptoms include penicillin, sulfonamides, gold compounds, hydralazine, isoniazid, and procainamide.

Is cutaneous lupus erythematosus contagious?

Cutaneous lupus erythematosus is not contagious. Patients do not need to be isolated and can interact, work, study, and socialize normally with others.

DIAGNOSIS

What tests are needed for the diagnosis of cutaneous lupus erythematosus?

Generally, cutaneous lupus erythematosus (CLE) is largely a clinical diagnosis, supported by appropriate background clinical features (e.g., known underlying systemic lupus erythematosus SLE).

If the diagnosis remains unclear (e.g., atypical clinical presentation or overlapping features with other skin conditions), confirmatory histopathological examination is required. Some patients with known SLE and/or typical clinical features of CLE may not require a biopsy.

Given the association between CLE and SLE, patients with CLE should be evaluated for SLE.

What diseases should cutaneous lupus erythematosus be differentiated from?

• Atypical acute cutaneous lupus erythematosus (ACLE) should be differentiated from dermatomyositis, scleroderma, vasculitis, seborrheic dermatitis, rosacea, and drug eruptions.

• Subacute cutaneous lupus erythematosus (SCLE) should be differentiated from polymorphic light eruption, psoriasis, erythema multiforme, granuloma annulare, and Henoch-Schönlein purpura.

• Atypical chronic cutaneous lupus erythematosus (CCLE) should be differentiated from granuloma annulare, lichen planus, lupus vulgaris, tertiary syphilis, actinic keratosis, sarcoidosis, common warts, and lymphocytic infiltration.

Key points for differentiation include the typical clinical manifestations, laboratory findings, and histopathological features of each disease. Direct immunofluorescence testing holds significant diagnostic value.

TREATMENT

Which department should I visit for cutaneous lupus erythematosus?

Rheumatology and Immunology, Dermatology.

How should cutaneous lupus erythematosus be treated?

The treatment of cutaneous lupus erythematosus (CLE) depends on the extent of disease involvement, CLE subtype, initial treatment response, and the presence of systemic lupus erythematosus (SLE).

Common first-line treatments include sun protection, topical corticosteroids, topical calcineurin inhibitors, and oral antimalarial drugs.

Topical treatments:

• Topical or intralesional corticosteroids: Mild or moderate potency for thin or delicate skin, while high or ultra-high potency or intralesional corticosteroid injections are used for hypertrophic or verrucous lesions.

• Calcineurin inhibitors: Such as tacrolimus ointment and pimecrolimus cream.

• Retinoids: Such as tazarotene gel and tretinoin cream, which can be used for discoid lupus erythematosus (DLE) with significant hyperkeratosis.

Systemic drug treatments:

• Antimalarial drugs: Antimalarials are the first-line systemic treatment, with an efficacy rate of over 80% for DLE, tumid lupus erythematosus, and subacute cutaneous lupus erythematosus (SCLE). Common options include hydroxychloroquine, chloroquine, and quinacrine. Hydroxychloroquine or chloroquine may be combined with quinacrine. Regular ophthalmologic examinations (every 3–6 months) are required to monitor ocular side effects.

• Corticosteroids: DLE and SCLE may require corticosteroids, typically at low to moderate doses, with gradual tapering after symptom control. ACLE diagnosed as SLE or progressing to SLE should follow SLE treatment guidelines.

• Immunosuppressants: These are mainly used for patients with inadequate response to conventional treatments. Options include azathioprine, methotrexate, mycophenolate mofetil, and cyclosporine. Side effects should be monitored and dosages adjusted accordingly.

• Other systemic treatments:

• Thalidomide: Used for recurrent or refractory cutaneous lupus erythematosus. Contraindicated in women planning pregnancy or during pregnancy.

• Dapsone: Primarily used for bullous SLE lesions and cases of DLE or SCLE unresponsive to conventional treatments.

• Retinoids: Mainly used for chronic and subacute cutaneous lupus erythematosus, particularly effective for verrucous lupus. Contraindicated in women planning pregnancy or during pregnancy.

• Biologics: Such as intravenous immunoglobulin, rituximab, belimumab, abatacept, anti-IL-6 monoclonal antibodies, and anti-IL-10 monoclonal antibodies, which may be used for severe cases like ACLE.

Can cutaneous lupus erythematosus be cured?

Most CLE lesions resolve with treatment, though some CCLE cases may leave atrophic scars, hyperpigmentation, or depigmentation. In rare cases, DLE lesions may persist long-term. New or worsening lesions often indicate disease activity.

CCLE and SCLE patients generally have a good prognosis due to the absence of major organ involvement. The prognosis for ACLE patients depends on the extent of organ involvement.

DIET & LIFESTYLE

What should patients with cutaneous lupus erythematosus pay attention to in their diet?

There are no special dietary restrictions; a healthy and balanced diet is sufficient.

• When cooking, use less salt, less oil, and fewer high-salt seasonings. Avoid pickled vegetables, cured meats, etc.;
• Do not rely solely on refined rice and white flour for staple foods. Replace some with whole grains, mixed beans, potatoes, pumpkins, etc.;
• Balance meat and vegetables. Prioritize white meats like chicken, duck, and fish, and limit fatty meats. Eggs and milk are important sources of protein and other nutrients;
• Vegetarians can eat more beans and bean products to supplement protein;
• Eat more fruits and vegetables;
• Avoid alcohol as much as possible.

What should patients with cutaneous lupus erythematosus pay attention to in daily life?

• Understand the disease correctly, prepare for long-term treatment, and cooperate actively with doctors.
• Avoid harmful stimuli and attend regular follow-ups.
• Protect against cold and sunlight, such as wearing sunglasses, using sunscreen, and wearing sun-protective clothing.

Do patients with cutaneous lupus erythematosus need follow-up examinations after treatment?

Yes, CLE patients should have regular follow-ups.

Routine laboratory tests should be performed during follow-ups, such as blood and urine tests. Liver and kidney function should be checked every 3–6 months, and immune function every 6–12 months. Assess whether the condition is stable or progressing to SLE. Monitor for adverse drug reactions.

Patients taking glucocorticoids should regularly check blood pressure and blood sugar. Those taking hydroxychloroquine or chloroquine should undergo eye examinations every 3–6 months.

PREVENTION

Can Cutaneous Lupus Erythematosus Be Prevented?

Since the exact pathogenesis is unclear, prevention is difficult. Daily precautions against UV exposure, such as wearing sunglasses, using sunscreen, and wearing sun-protective clothing, are recommended.