erythematosus

Erythematosus is a medical suffix used to denote conditions with erythema or inflammation of the skin or mucous membranes. It is not a disease in itself. The term is best known from lupus erythematosus, a group of autoimmune disorders that may affect the skin and other organs.

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease, commonly involving the skin, joints, kidneys, and nervous system. Cutaneous forms include discoid lupus erythematosus (DLE), which causes chronic scaly plaques on sun-exposed areas, and subacute cutaneous lupus erythematosus (SCLE), with annular or psoriasiform lesions. Neonatal lupus erythematosus and drug-induced lupus erythematosus (DILE) are recognized variants arising from maternal autoantibodies or certain medications, respectively.

Pathophysiology centers on immune dysregulation with autoantibody production. In SLE, autoantibodies to double-stranded DNA and ribonucleoproteins contribute to inflammation through immune complex deposition and complement activation.

Diagnosis relies on clinical features supported by laboratory tests, including antinuclear antibodies (ANA) and disease-specific antibodies, along with organ involvement assessment. Skin biopsy can aid in diagnosing cutaneous disease.

Treatment is disease-specific. Skin-limited disease often uses sun protection and topical therapies; hydroxychloroquine is a common systemic therapy for many forms; more extensive disease may require corticosteroids or other immunosuppressants. Drug-induced lupus usually resolves after stopping the offending medication.

Prognosis varies widely; cutaneous lupus can be managed effectively with therapy, while systemic disease can cause lasting organ damage and requires ongoing care.