From the Guidelines
Evanescent rash is not a characteristic feature of systemic lupus erythematosus (SLE), and its presence should prompt consideration of alternative diagnoses, such as Still's disease. When evaluating a patient with an evanescent rash, it is essential to distinguish it from the typical skin manifestations of SLE, which include a fixed, erythematous malar or "butterfly" rash, discoid lesions, photosensitive rashes, and subacute cutaneous lupus lesions 1. The management of SLE skin manifestations, as recommended by the 2019 EULAR guidelines, typically involves hydroxychloroquine at a dose not exceeding 5 mg/kg real body weight, as well as minimization of glucocorticoids to less than 7.5 mg/day (prednisone equivalent) during chronic maintenance treatment 1. Key features of Still's disease, which may be considered in the differential diagnosis, include:
- Quotidian fevers
- Arthralgia or arthritis
- Sore throat
- Lymphadenopathy
- Elevated ferritin levels In contrast to SLE, the evanescent rash in Still's disease is thought to be related to neutrophilic urticaria and cytokine dysregulation, particularly IL-1 and IL-6. Given the distinct pathophysiology and clinical features of these conditions, a thorough diagnostic evaluation is necessary to determine the underlying cause of an evanescent rash and guide appropriate management.
From the Research
Evanescent Rash and SLE
- Evanescent rash can be a symptom of Systemic Lupus Erythematosus (SLE), a multiorgan autoimmune disease with many clinical manifestations 2.
- The skin is one of the target organs most variably affected by SLE, and cutaneous lesions account for four of the 11 revised criteria of SLE 2.
- SLE-specific cutaneous changes include malar rash, discoid rash, photosensitivity, and oral mucosal lesions, while nonspecific skin manifestations can also occur 2, 3.
- Recognizing specific cutaneous lesions in SLE, such as the "butterfly" rash, is important for early diagnosis and estimating the associated risks of internal disease 3.
- Nonspecific lesions, such as exanthema, vasculitis, and alopecia, can be part of SLE flares, and their presence can contribute to early diagnosis and effective patient management 3.
Treatment and Management
- Hydroxychloroquine (HCQ) is a commonly used drug in the treatment of SLE, and its use has been shown to decrease SLE activity, prevent disease flare, and lower the long-term glucocorticoid need 4, 5, 6.
- HCQ has several beneficial effects, including antithrombotic and metabolic effects, and its use has been recommended in all patients with SLE unless contraindications or side effects are present 6.
- The daily dose of HCQ associated with the best compromise between efficacy and safety is a matter of debate, with a currently agreed-upon daily dosage of ≤5 mg/kg/day actual body weight 6.
- Glucocorticoids (GCs) should be used judiciously, with methyl-prednisolone pulses as the main therapy for inducing rapid remission and doses ≤5-2.5 mg/day not exceeded in long-term maintenance treatments 4.