Subacute Cutaneous Lupus Erythematosus

Subacute cutaneous lupus erythematosus is an autoimmune disease that primarily affects the skin, causing distinctive red rashes and lesions on sun-exposed areas of the body. While there is no cure, understanding the condition and working with healthcare providers can help manage symptoms and maintain quality of life.

Table of contents

• What is subacute cutaneous lupus erythematosus?
• Alternative names
• Medical classification codes
• Who develops this condition?
• What causes subacute cutaneous lupus erythematosus?
• What are the symptoms?
• How is it diagnosed?
• Possible complications
• Treatment options
• Living with the condition
• What to expect

What is subacute cutaneous lupus erythematosus?

Subacute cutaneous lupus erythematosus (SCLE) is a form of cutaneous lupus erythematosus (a type of lupus that affects your skin). The term subacute refers to the depth of inflammation seen when a skin sample is examined under a microscope. People with SCLE develop distinctive rashes on sun-exposed areas of their body, particularly on the neck, shoulders, arms, back, and chest^[1].

SCLE is one form of cutaneous lupus. Other forms include acute cutaneous lupus erythematosus and chronic cutaneous lupus erythematosus (which includes discoid lupus erythematosus)^[2]. Unlike these other forms, SCLE typically does not cause scarring, though it may leave skin discoloration after the rash heals^[1].

About half of people with subacute cutaneous lupus also have the more common form of lupus called systemic lupus erythematosus (SLE), which can affect multiple organs throughout the body^[1]. However, when SCLE occurs with SLE, the systemic symptoms tend to be milder, and serious complications involving the kidneys or nervous system are less common than in people with SLE alone^[3].

Alternative names

Subacute lupus erythematosus, SCLE

Medical classification codes

L93.2; L93.1; M32.0

Who develops this condition?

SCLE affects about 10% of all patients with lupus^[4]. While anyone can develop this condition regardless of age, sex, or ethnicity, certain groups have a higher risk. SCLE is most commonly diagnosed in middle-aged women, particularly those between the ages of 40 and 60^[1]. In North America, the condition is more common in white people than in other ethnic groups^[4].

Lupus has a strong genetic component, meaning it runs in families. If you have a biological parent with lupus, you may have an increased risk of developing the condition^[1].

SCLE can be associated with other diseases. Some people with SCLE also have Sjögren syndrome, rheumatoid arthritis, or Crohn disease^[4].

What causes subacute cutaneous lupus erythematosus?

SCLE is an autoimmune disease, which means your body’s immune system mistakenly attacks healthy tissue instead of protecting you from infection. In this condition, the immune system attacks the skin, causing inflammation^[6].

The exact cause is complex and not fully understood. Researchers believe it involves a combination of genetic factors and environmental triggers. Studies have found that SCLE is associated with certain genetic markers, particularly specific types of human leukocyte antigens (HLA), including HLA-B8, HLA-DR3, HLA-DRw52, and HLA-DQ1^[3]. More than 70% of patients with SCLE have antibodies called anti-Ro (SS-A) antibodies in their blood^[3].

Environmental factors play an important role in triggering the condition. The most significant trigger is exposure to ultraviolet (UV) light from the sun or other sources. When skin is exposed to UV radiation, it can increase the expression of certain proteins on skin cells, leading to an immune response that causes the rash^[4].

Other potential triggers include smoking, stress, and exposure to certain pesticides or toxins^[1].

Drug-induced subacute cutaneous lupus

In about one-third of people with SCLE, the condition develops after taking certain medications^[1]. It is estimated that 20-40% of cases of SCLE are drug-induced^[4]. The time between starting a medication and developing the rash can vary widely, from a few days to several years^[4].

Medications most commonly associated with SCLE include^[1][4]:

• Thiazide diuretics (water pills used for blood pressure)
• Terbinafine (an antifungal medication)
• Calcium channel blockers (blood pressure medications)
• Proton pump inhibitors or PPIs (medications for acid reflux and heartburn)
• ACE inhibitors (blood pressure medications)
• Anti-seizure medications
• Chemotherapy medications
• Tumor necrosis factor inhibitors (used for autoimmune diseases)

If a medication is causing your SCLE, stopping the drug in consultation with your doctor may help, though the rash may take more than six months to resolve in some cases^[6].

What are the symptoms?

The main symptom of subacute cutaneous lupus is a rash that typically appears on sun-exposed areas of your body, such as your neck, chest, back, shoulders, and the outer surfaces of your arms. The face is usually not affected or only minimally affected^[2].

Types of rashes

There are two main patterns of SCLE rashes^[1][4]:

Annular SCLE causes red, raised, ring-shaped lesions with clear centers. These rings can spread and connect to form overlapping or interlocking circular patterns. When these lesions heal, they may leave areas of lighter skin (called hypopigmentation), but they do not cause scarring.

Papulosquamous SCLE causes red, bumpy, scaly patches that may resemble psoriasis or eczema. This type also appears on sun-exposed areas and does not typically cause scarring.

Some people may have both types of rashes at the same time. Occasionally, the rashes may have blisters, crusting, or small fluid-filled bumps at the edges^[4].

An important characteristic of SCLE rashes is that they typically do not itch or cause scarring. However, when the rash clears up, it may leave skin discoloration that can be noticeable. Normal skin color usually returns over time^[4].

Other symptoms

Some people with SCLE experience additional symptoms, including^[4][6]:

• Hair loss (usually temporary and does not leave scarring)
• Mouth ulcers
• Joint pain or muscle aches
• Fatigue (feeling tired all the time)
• Small blood vessels visible near the nails

Most people with SCLE feel relatively well overall, though some may notice symptoms such as fatigue or joint aches^[6].

How is it diagnosed?

A dermatologist (a doctor specializing in skin, hair, and nails) or a rheumatologist (a doctor specializing in arthritis and autoimmune diseases) can diagnose subacute cutaneous lupus^[1].

Diagnosis is primarily based on clinical evaluation of the characteristic skin lesions, along with laboratory tests. Your doctor will examine your skin and ask detailed questions about your symptoms, including when they started, whether they get worse with sun exposure, and what medications you take^[6].

Skin biopsy

In some cases, your provider may request a skin biopsy to confirm the diagnosis. During this procedure, your provider removes a small sample of skin, which is sent to a laboratory to be examined under a microscope. This examination can determine whether a skin rash is due to lupus or another condition^[1].

When there is doubt about the diagnosis, a technique called direct immunofluorescence may be used. This test looks for a specific pattern of immune protein deposits at the junction between different layers of skin^[4].

Blood tests

Your doctor will likely order blood tests to look for specific antibodies (proteins made by the immune system). The most important antibodies in SCLE are called anti-Ro/SSA and anti-La/SSB. More than 70% of people with SCLE test positive for anti-Ro antibodies^[4][6].

Other blood and urine tests may be performed to check whether you have systemic lupus erythematosus affecting other organs, such as the kidneys^[1][6].

Possible complications

About 50% of patients with SCLE meet the criteria for a diagnosis of systemic lupus erythematosus^[4]. However, when SCLE occurs together with SLE, the systemic disease is usually milder, with less frequent involvement of the kidneys and nervous system compared to people with SLE who do not have SCLE^[3].

Because people with SCLE must protect themselves extensively from sun exposure, they may develop vitamin D deficiency. Your doctor may recommend vitamin D supplements^[1].

SCLE can lead to significant skin discoloration and may affect your quality of life and emotional well-being. The visible changes to your skin, combined with the need to avoid the sun and manage a chronic condition, can be challenging^[1].

Special considerations for pregnancy

If you are a woman with SCLE who has anti-Ro/SSA or anti-La/SSB antibodies and you become pregnant, there is a small risk that these antibodies could affect your baby. About 8-10% of babies born to mothers with these antibodies may develop neonatal lupus erythematosus, which causes a temporary rash. More seriously, 1-2% may develop congenital heart block, a permanent condition affecting the heart’s rhythm^[4]. If you are considering pregnancy, it is important to discuss these risks with your doctor^[6].

Treatment options

While there is no cure for SCLE, treatment can help manage symptoms, prevent new lesions from forming, and reduce the frequency of flare-ups. The main goals are to improve your rashes, minimize discomfort, and prevent complications^[1].

Sun protection

The most important part of managing SCLE is strict protection from the sun. This includes^[12][6]:

• Using broad-spectrum sunscreen with SPF 50 or higher every day, even on cloudy days
• Applying sunscreen at least 20 minutes before going outside
• Reapplying sunscreen every 2-3 hours when outdoors
• Wearing protective clothing, including long sleeves, long pants, and wide-brimmed hats
• Avoiding the sun during peak hours (usually 10 a.m. to 4 p.m.)
• Seeking shade whenever possible

Without adequate sun protection, SCLE can be very challenging to control^[12].

Topical treatments

For mild to moderate SCLE, your doctor may prescribe topical (applied to the skin) medications, most commonly strong or very strong corticosteroids (steroid creams or ointments) to reduce inflammation^[6].

Antimalarial medications

Antimalarial drugs are the standard systemic (taken by mouth) treatment for SCLE. The most commonly prescribed is hydroxychloroquine. Another option is chloroquine. These medications can reduce pain and inflammation, prevent flare-ups, and help control skin problems^[12].

For people who do not respond well to hydroxychloroquine alone, adding another antimalarial drug called quinacrine may improve results^[12].

Antimalarial medications can take several weeks or months to show their full effect, so patience is important. Regular eye examinations are needed while taking these medications, as they can rarely affect vision^[12].

Other medications

If antimalarials do not provide adequate control, other treatments may be considered, including^[12]:

• Methotrexate (an immunosuppressant drug)
• Dapsone (particularly helpful for certain types of lesions)
• Retinoids (vitamin A-related medications)
• Mycophenolate mofetil (an immunosuppressant)

For people with severe SCLE that does not respond to standard treatments, newer medications called biologics may be options. These include rituximab and belimumab, which work by targeting specific parts of the immune system^[12].

Lifestyle modifications

In addition to medications, certain lifestyle changes can help manage SCLE^[6]:

• If you smoke, quitting is important, as smoking can worsen lupus and make it harder to control
• Avoiding medications known to trigger SCLE (after consulting with your doctor)
• Managing stress, as it may trigger flare-ups

Monitoring and follow-up

Regular visits to your healthcare provider are essential. Your doctor will monitor your skin condition, check for signs of systemic lupus, and watch for any medication side effects. Blood and urine tests may be performed periodically to ensure that lupus is not affecting other organs^[6].

Living with the condition

Living with SCLE can be challenging, but many people learn to manage the condition successfully and maintain their quality of life. Here are some important points to keep in mind:

Take your medications exactly as prescribed by your doctor. If you think you are having side effects or if your medication does not seem to be working, contact your healthcare provider rather than stopping the medication on your own. Consistency with treatment is one of the most important factors in controlling lupus.

Learn about your condition. The more you understand about SCLE, including what triggers your flare-ups, the better you will be at preventing them and managing symptoms. Keep track of when flare-ups occur and what you were doing or experiencing beforehand, as this can help identify your personal triggers.

Protect yourself from the sun every day, not just when it is sunny. UV light can penetrate clouds and even windows. Make sun protection a daily habit.

Connect with others who have lupus. Support groups, either in your community or online, can provide valuable emotional support and practical advice from people who understand what you are experiencing^[1].

Pay attention to your emotional well-being. Living with a chronic condition can affect your mental health. If you feel overwhelmed, anxious, or depressed, talk to your healthcare provider about getting support.

Maintain regular communication with your healthcare team. Let your doctor know immediately if you develop new symptoms, have signs of infection, or notice changes in your condition. Regular check-ups help catch problems early.

What to expect

SCLE is a chronic condition, meaning it is long-lasting and requires ongoing management. The condition typically comes and goes in cycles, with periods of active disease (flare-ups) alternating with periods when symptoms are mild or absent (remission)^[1].

The good news is that SCLE lesions heal without scarring or atrophy, though they may cause temporary skin discoloration. Normal skin color usually returns over time^[3][4].

With proper treatment and sun protection, many people with SCLE can keep their condition well controlled. While severe systemic disease is unusual in SCLE, it is important to maintain regular follow-up with your healthcare provider to monitor for any development of systemic symptoms^[3].

If your SCLE is drug-induced, withdrawing the offending medication (with your doctor’s guidance) along with medical therapy may lead to improvement, though this can take time^[3].

Working closely with a dermatologist or rheumatologist who listens to your concerns and helps you find the right treatment approach is essential. Look for a healthcare provider who will partner with you to manage the condition. With the right care and self-management strategies, most people with SCLE can continue their daily activities and lead fulfilling lives^[1].