Urticarial vasculitis and urticarial autoinflammatory syndromes.

Area of Science:

• Dermatology
• Immunology
• Rheumatology

Background:

• Urticaria is a common disorder with acute and chronic forms, presenting as wheals, sometimes with angioedema.
• Several conditions can manifest as urticarial skin lesions, necessitating differentiation from ordinary urticaria.
• Urticarial vasculitis (UV) and autoinflammatory diseases (e.g., cryopyrin-associated periodic syndromes, CAPS, and Schnitzler's Syndrome) are key differential diagnoses.

Purpose of the Study:

• To review urticarial vasculitis (UV) and specific autoinflammatory diseases (CAPS, Schnitzler's Syndrome) as important differential diagnoses for common urticaria.
• To highlight the distinct clinical and histological features of UV and CAPS compared to ordinary urticaria.
• To emphasize the importance of accurate diagnosis for appropriate treatment and prevention of systemic complications.

Main Methods:

• Review of literature focusing on urticarial vasculitis and cryopyrin-associated periodic syndromes (CAPS).
• Comparison of clinical presentation, duration of lesions, and associated symptoms of UV, CAPS, and common urticaria.
• Analysis of histological findings in UV (leukocytoclastic vasculitis) and CAPS (neutrophilic infiltrate).

Main Results:

• Urticarial vasculitis presents with wheals lasting >24 hours, burning sensation, and potential purpura or bullae, with leukocytoclastic vasculitis on histology.
• Cryopyrin-associated periodic syndromes (CAPS) result from NLRP3 gene mutations, leading to IL-1β overproduction and neutrophilic infiltrate in lesions.
• Neither UV nor CAPS respond to antihistamines, unlike common urticaria.

Conclusions:

• Urticarial vasculitis and CAPS are distinct conditions that can be misdiagnosed as common urticaria.
• Accurate differentiation is essential as UV and CAPS require specific treatments beyond antihistamines.
• Timely and correct diagnosis can prevent serious systemic complications associated with these urticarial syndromes.