What Is Acute Cutaneous Lupus?

Overview 

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that varies in severity, characterised by periodic flare-ups. Lupus erythematosus (LE) is an autoimmune disease with diverse classifications based on its manifestations. The primary categories include systemic lupus erythematosus (SLE), affecting multiple organs and systems, and cutaneous lupus erythematosus (CLE), primarily impacting the skin.¹ 

CLE is further subdivided into three subtypes: acute cutaneous lupus erythematosus (ACLE), identified by a rash on sun-exposed areas; subacute cutaneous lupus erythematosus (SCLE), displaying light-sensitive skin lesions; and chronic cutaneous lupus erythematosus (CCLE), associated with persistent skin manifestations. Additionally, drug-induced lupus erythematosus (DILE) resembles SLE but arises from specific medications. 

What is acute cutaneous lupus? 

Acute cutaneous lupus erythematosus (ACLE) is a common autoimmune disease and is the most common type of skin lesion associated with systemic lupus erythematosus. ACLE can present as either localised or widespread, and its characteristic rash typically appears on sun-exposed areas such as the face, neck, and arms. ACLE is considered one of the subsets of cutaneous lupus erythematosus (CLE), and the rash may be temporary or persistent in nature. ACLE is estimated to occur in approximately 30% to 50% of individuals diagnosed with systemic lupus erythematosus (SLE).² In some cases, patients with cutaneous lupus erythematosus (CLE) may experience multiple forms of the condition simultaneously. 

A research study involving 191 CLE patients revealed that 68% exhibited one type of CLE, 29% displayed two types, and 3% presented with three types of CLE concurrently.³ The prevalence of systemic lupus erythematosus (SLE) differs among populations and regions worldwide. Rough estimates indicate that SLE affects approximately 20 to 150 individuals per 100,000 people globally. However, the specific proportion of SLE patients who develop acute cutaneous lupus erythematosus (ACLE) can vary.

Causes of acute cutaneous lupus 

The occurrence of systemic lupus erythematosus (SLE), including acute cutaneous lupus erythematosus (ACLE), differs among diverse populations and ethnicities. People assigned female at birth (AFAB) are more commonly affected than those assigned male at birth (AMAB), and the highest frequency of onset is typically observed during the reproductive years, specifically between the ages of 15 and 45.⁴ Nonetheless, ACLE can affect individuals of any age and gender. 

The specific aetiology (cause) of acute cutaneous lupus erythematosus (ACLE) is not fully understood. However, it is hypothesised that both genetic factors and environmental triggers, such as sun exposure, contribute to its development.¹ ACLE is characterised as an autoimmune disorder wherein the immune system erroneously targets healthy skin cells. This leads to skin inflammation and the formation of characteristic lesions. A comprehensive investigation is necessary to gain a comprehensive understanding of the intricate mechanisms underlying the development of ACLE. 

Exposure to ultraviolet (UV) radiation is strongly linked to disease activity in cutaneous lupus erythematosus (CLE).⁵ Sunlight, which emits UV radiation, can induce and worsen skin lesions in individuals with CLE. The skin manifestations of CLE, including rashes and inflammation, are particularly sensitive to UV exposure. Furthermore, UV radiation can intensify systemic symptoms such as arthralgia (joint pain) and fatigue in individuals with CLE. The exact mechanisms underlying this association are not fully understood, but it is believed that UV light triggers an immune response in the skin, leading to inflammation and the release of inflammatory mediators. To mitigate the effects of UV radiation, individuals with CLE should adopt sun protection measures such as wearing protective clothing, using sunscreen, and seeking shade during peak sun hours. By taking these precautions, individuals with CLE can minimise the triggering and exacerbation of symptoms, ultimately improving the management of the condition.

Signs and symptoms of acute cutaneous lupus

Acute cutaneous lupus erythematosus (ACLE) commonly occurs during the third decade of life and is often seen alongside active systemic lupus erythematosus (SLE).⁶ 

ACLE typically manifests on the face, specifically as malar erythema (a symmetrical rash in the shape of a butterfly over the nose bridge and cheeks), but can extend to affect the entire body.⁷ In the generalised variant, a morbilliform eruption (small circular lesions, which are red and may be flat or raised) is observed predominantly on the arms. When the trunk is involved, a triangular pattern of lesions is frequently seen. 

ACLE may present with additional manifestations, including telangiectasias (dilated blood vessels), mouth ulcers, poikiloderma (patchy discolouration of the skin), scales, and erosions. 

Management and treatment for acute cutaneous lupus

The objective in managing the cutaneous manifestations of systemic lupus erythematosus (SLE) is to prevent and treat skin activity in order to minimise damage. A crucial aspect of managing cutaneous disease in SLE is prevention, which involves implementing rigorous sun protection measures such as⁷:

• Wearing protective clothing 
• Avoiding peak sunlight hours
• Applying broad-spectrum ultraviolet A/B sunscreens with a minimum SPF of 70
• It is recommended to consider vitamin D supplementation, especially when levels are below the normal range 
• Patients who smoke should receive counselling on quitting smoking, as it is associated with an increased risk of widespread cutaneous lupus erythematosus (CLE) and worsened disease severity

For the treatment of acute cutaneous lupus erythematosus (ACLE), the first-line approach involves general preventive measures such as sun protection and smoking cessation. Local treatments may include the application of topical steroids or calcineurin inhibitors, particularly for mild cases. 

Antimalarial drugs like hydroxychloroquine and chloroquine are recommended for treating ACLE. These medications have shown significant clinical improvement in ACLE cases, as demonstrated by multiple studies, including a recent meta-analysis that reported a substantial response rate of 91% in ACLE cases.⁵ In severe or refractory cases, short courses of oral corticosteroids may be necessary, especially during flare-ups, as a bridge to slower-acting steroid-sparing medications. However, the chronic use of systemic steroids should be avoided due to their multiple adverse effects.

Diagnosis

The diagnosis of cutaneous lupus erythematosus (CLE) involves a combination of clinical assessments, serologic testing (blood tests to identify antibodies), and biopsy findings. To accurately diagnose cutaneous manifestations of lupus, it is crucial for physicians to correctly classify the subtype and rule out systemic involvement of the disease.

Diagnosing CLE solely based on the American College of Rheumatology (ACR) criteria should be avoided since these criteria were designed to distinguish between different autoimmune diseases. Instead, CLE diagnosis should rely on patient history, clinical examination, laboratory studies, serology, as well as histology and direct immunofluorescence (DIF) examination of skin biopsies when histology alone is not sufficient.

Skin biopsy of acute cutaneous lupus erythematosus (ACLE) reveals specific histological findings, such as degeneration of the lowest layer of skin, upper dermal oedema (skin swelling), infiltration of immune cells, and hyperkeratosis (thickened outer layer of skin).⁵ 

Direct immunofluorescence (DIF) can be helpful in differentiating cutaneous lupus from other inflammatory skin conditions. It can show a "lupus band" in the majority of ACLE cases, which refers to a granular deposition of components of the immune system, such as immunoglobulins (antibodies).⁷ While a positive lupus band test supports the diagnosis of ACLE, a negative DIF does not rule it out.

FAQs

How can I prevent acute cutaneous lupus?

Preventing acute cutaneous lupus erythematosus (ACLE) involves minimising sun exposure, implementing sun protection measures, avoiding photosensitivity triggers, quitting smoking, ensuring regular medical care, and adopting a healthy lifestyle.⁷

How common is acute cutaneous lupus?

The global prevalence of acute cutaneous lupus erythematosus (ACLE) as a distinct subtype is not extensively documented, but it is commonly seen in the context of systemic lupus erythematosus (SLE), which has an estimated incidence of 20 to 150 cases per 100,000 individuals worldwide.

Who is at risk of acute cutaneous lupus?

People with systemic lupus erythematosus (SLE), particularly people AFAB in their 30s, are at an increased risk of developing acute cutaneous lupus erythematosus (ACLE), although ACLE can affect individuals of any age, gender, or ethnic background, and excessive sun exposure is a recognised risk factor.

When should I see a doctor?

If you observe persistent or worsening skin changes, have symptoms related to systemic lupus erythematosus (SLE), suspect lupus-related issues, or experience emotional and psychological impact, it is advised to seek medical advice and support from a healthcare professional.

Summary 

Acute cutaneous lupus erythematosus (ACLE) has significant impacts worldwide. It causes physical symptoms like skin rashes and lesions, leading to discomfort and potential scarring. The visible nature of the condition can also impact emotional well-being, causing self-consciousness and lowered self-esteem. ACLE can affect daily activities and quality of life due to sensitivity to sunlight and the limitations it imposes. Managing ACLE requires medical care and treatment, which can result in a burden on individuals and healthcare systems. Proper medical care and support are crucial for effectively managing ACLE and improving the quality of life for those affected.