Systemic lupus erythematosus - Nail and Distal Digit
Patients typically show concurrent skin findings that are more specific for SLE, including malar erythema or discoid lesions. Treatment of SLE may lead to correction of specific nail abnormalities.
Patients with SLE frequently show abnormalities of the vasculature of the nail folds marked by periungual erythema, splinter hemorrhages, and nail fold infarcts. Nail fold capillaroscopy evaluation in patients with SLE has revealed abnormalities of the microvasculature in 20%-93% of patients that include tortuous, elongated, dilated capillary loops. These findings are not specific for SLE but may correlate with disease severity.
M32.9 – Systemic lupus erythematosus, unspecified
55464009 – Systemic lupus erythematosus
Differential Diagnosis & Pitfalls
- Drug-induced SLE
- Dermatomyositis – Characteristic heliotrope rash (violaceous plaques surrounding eyes), photodistributed cutaneous eruption, and nail fold changes. Look for elevated serum creatine kinase (CK) levels and proximal symmetric extremity weakness.
- Phototoxic / photoallergic drug eruptions
- CREST syndrome – Can have overlap with dermatomyositis. Refers to a subset of patients with limited scleroderma.
- Scleroderma – Check for anticentromere antibodies and anti-Scl-70 antibodies. Typified by sclerotic changes in skin not seen in dermatomyositis.
- Mixed connective tissue disease – Check for anti-U1RNP antibody. Most patients are positive for this in mixed connective tissue disease.
- Raynaud phenomenon – No systemic involvement.
- Chilblains (perniosis)