Hypocomplementemic Urticarial Vasculitis with Rhupus Syndrome: A Literature Review and Clinical Case

Introduction: Hypocomplementemic urticarial vasculitis (HUV) is a rare immune-mediated disorder characterized by persistent urticarial lesions. Rhupus syndrome involves two connective tissue diseases: systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Due to its rarity and varied symptoms, the coexistence of HUV and Rhupus presents a unique clinical and therapeutic challenge. Case Presentation: A 37-year-old woman presented with a 4-year history of symmetrical arthritis, non-scarring alopecia, and bilateral episcleritis. She also had non-granulomatous anterior uveitis in her right eye. Immunologic tests showed the following: antinuclear antibodies of 1:1,000, rheumatoid factor of 110 IU/mL, anti-CCP of greater than 200 UR/mL, anti-SS-A/Ro of 172.47 UR/mL, and anti-SS-B/La of 16.43 UR/mL. Complement testing revealed low C4 levels (7.35 mg/dL) and normal C3 levels (81.2 mg/dL). Based on the patient’s clinical and serological findings, she met the 2019 EULAR/ACR classification criteria for RA and LES, which supports a diagnosis of Rhupus. Over the past 10 months, she has experienced persistent, painful, itchy, generalized wheals lasting over 24 h that resolve with post-inflammatory hyperpigmentation. A skin biopsy confirmed leukocytoclastic vasculitis, which supports a diagnosis of HUV. Conclusion: Patients with autoimmune diseases such as SLE or RA who experience persistent urticarial eruptions associated with systemic signs should be evaluated for HUV. Concurrently, diagnosing HUV and Rhupus is extremely rare and requires a comprehensive approach. Personalized treatment plans and multidisciplinary care are essential for managing these complex overlap syndromes.