Acute Onset of Large Erythematous Lesions in Patient with Systemic Lupus Erythematosus

Case at a Glance

A 32-year-old female with known systemic lupus erythematosus presented with acute onset of large, raised, erythematous lesions on bilateral lower extremities accompanied by intense pruritus and localized pain.

Patient's Story

The patient, a 32-year-old female (height 5'10", weight 160 lbs) with a medical history significant for systemic lupus erythematosus and food sensitivities to gluten and dairy, presented with a 24-hour history of skin lesions. She reported that around midday, she first noticed a hot, itching sensation under her left knee and on the top of her right thigh. By evening, these areas had become visibly raised and erythematous. The lesions continued to enlarge and become increasingly pruritic over the following hours. Each lesion measured approximately 3 inches in diameter, felt like a single large raised mass, and was tender to touch, resembling bruise-like soreness. The patient initially suspected sun exposure despite using sunscreen and UPF clothing, but the clinical presentation suggested an alternative etiology. Treatment with antihistamines (Zyrtec) provided no symptomatic relief.

Initial Assessment

Physical examination revealed bilateral lower extremity lesions: one located in the popliteal region of the left knee and another on the anterior aspect of the right thigh. The lesions appeared as large, well-demarcated, raised erythematous plaques with associated warmth and tenderness on palpation. The patient was afebrile and denied systemic symptoms.

The Diagnostic Journey

Given the patient's history of autoimmune disease and the acute presentation of large inflammatory skin lesions, differential diagnosis included lupus-related skin manifestations, drug-induced reactions, contact dermatitis, cellulitis, or other inflammatory dermatoses. The bilateral distribution and acute onset raised concern for systemic involvement or medication-related adverse effects.

Final Diagnosis

Clinical evaluation suggested acute inflammatory dermatitis, possibly related to the patient's underlying autoimmune condition or representing a hypersensitivity reaction. Further dermatological consultation was recommended for definitive diagnosis and management.

Treatment Plan

Immediate management included discontinuation of antihistamine therapy due to lack of efficacy. Patient was advised to seek urgent dermatological evaluation for visual and tactile examination, as remote assessment was deemed insufficient for accurate diagnosis. Consideration for topical anti-inflammatory agents, systemic corticosteroids, or adjustment of current immunosuppressive therapy pending specialist evaluation.

Outcome and Follow-up

Patient was counseled on the importance of in-person medical evaluation given the complexity of the presentation and potential relationship to her underlying lupus condition. Close monitoring for lesion progression, development of additional symptoms, or signs of systemic involvement was recommended pending specialist consultation.