From the Guidelines
A patient with a malar rash should undergo a comprehensive evaluation focused on diagnosing systemic lupus erythematosus (SLE) and other connective tissue diseases, as recommended by the 2019 EULAR guidelines for the management of SLE 1. The workup should begin with a detailed history and physical examination, looking for associated symptoms like joint pain, photosensitivity, oral ulcers, and systemic manifestations.
Key Components of the Workup
- Laboratory testing should include:
- Complete blood count
- Comprehensive metabolic panel
- Urinalysis
- Erythrocyte sedimentation rate
- C-reactive protein to assess for inflammation
- Specific autoimmune testing should include:
- Antinuclear antibody (ANA)
- Anti-double-stranded DNA
- Anti-Smith
- Anti-Ro/SSA
- Anti-La/SSB antibodies
- Complement levels (C3, C4) A skin biopsy of the rash may be necessary to confirm the diagnosis histologically.
Additional Testing and Consultation
Additional testing based on clinical presentation might include:
- Chest X-ray
- Electrocardiogram
- Renal function tests to evaluate for organ involvement Early rheumatology consultation is recommended for patients with positive autoimmune markers or strong clinical suspicion of SLE, as prevention of disease flares is an important milestone of SLE treatment 1. This comprehensive approach is essential because the malar rash, while classically associated with SLE, can also appear in dermatomyositis, rosacea, seborrheic dermatitis, and photosensitivity reactions, making accurate diagnosis crucial for appropriate management.
From the Research
Workup for a Patient with a Malar Rash
The presence of a malar rash, also known as a butterfly rash, is a common symptom of Systemic Lupus Erythematosus (SLE) 2. When evaluating a patient with a malar rash, the following steps should be taken:
- Obtain a detailed medical history to identify any potential triggers or underlying conditions
- Perform a physical examination to assess the extent and characteristics of the rash
- Order laboratory tests to rule out other potential causes of the rash and to assess for any organ involvement
Differential Diagnosis
A generalized rash, such as a malar rash, can have several potential causes, including:
- Contact dermatitis
- Atopic eczema
- Sun-induced damage
- Drug eruption
- Systemic diseases or infections 3 A thorough history and physical examination are essential to narrow down the differential diagnosis and guide further testing and treatment.
Treatment Options
For patients with SLE, hydroxychloroquine (HCQ) is a commonly used treatment option 4, 5, 6. HCQ has been shown to reduce the risk of flares, allow for the reduction of steroid dosage, and prevent organ damage. It is generally safe and can be prescribed to pregnant women. However, caution is needed to prevent retinopathy, a rare but serious complication of prolonged HCQ use.
Management
The management of a patient with a malar rash and suspected SLE involves a multidisciplinary approach, including:
- Dermatologists to assess and manage the skin manifestations
- Rheumatologists to assess and manage the underlying autoimmune disease
- Other specialists as needed to address any organ involvement or other complications A thorough understanding of the cutaneous manifestations of SLE is essential for diagnosis, prognosis, and efficient management 2.