Urticarial Vasculitis

Prepared and reviewed by the PrepElephant Academic Review Team

First published 14 Oct 2026 · Spot an error?

Reference basis: Rook's Textbook of Dermatology; IADVL Textbook of Dermatology

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Direct answer
What you must remember
Separating urticarial vasculitis from chronic urticaria
Where the exam tries to catch you
Frequently asked questions
Related topics

Direct answer

Urticarial vasculitis is a form of leukocytoclastic vasculitis that mimics urticaria, but its wheals last longer than 24 hours and fade leaving bruising or pigmentation. The lesions burn or ache rather than itch predominantly. Low complement, especially C1q, identifies the hypocomplementaemic variant, which is often linked with systemic lupus erythematosus.

What you must remember

Duration: individual wheals persist beyond 24 hours, the single feature that most separates urticarial vasculitis from ordinary urticaria.
Residual change: fading lesions leave bruising, purpura or brownish staining, which ordinary wheals never do.
Sensation: burning or pain predominates over itch, a clue that examiners expect you to notice.
Histology: leukocytoclastic vasculitis of postcapillary venules, a finding absent in ordinary urticaria.
Complement: low C1q, C3 or C4 marks the hypocomplementaemic form, which is linked with anti-C1q antibodies.
Associations: systemic lupus erythematosus, Sjogren syndrome and monoclonal gammopathy need screening.
Organ involvement: the hypocomplementaemic form can affect the eyes, lungs and kidneys.
Treatment: antihistamines work less well than in ordinary urticaria, so hydroxychloroquine, dapsone, colchicine or systemic steroids are added.

Separating urticarial vasculitis from chronic urticaria

A 38-year-old woman has had itchy wheals for several months, but some lesions last two days, leave brown marks and burn. Her antihistamines have given only partial control.

Time each wheal: lesions lasting longer than 24 hours make ordinary urticaria unlikely and direct attention towards vasculitis.
Look at the residue: persistent bruising, purpura or brown staining after a wheal fades supports a vasculitic process.
Biopsy a persisting lesion: a biopsy showing leukocytoclastic vasculitis, with neutrophils and nuclear debris in the venular wall, confirms the diagnosis.
Measure complement: low C1q, C3 or C4 indicates the hypocomplementaemic subtype, which carries more systemic risk.
Screen for systemic disease: antinuclear antibody, lupus workup, a Sjogren screen and serum protein electrophoresis identify the underlying condition.
Treat and monitor: a non-sedating antihistamine is the starting point, with hydroxychloroquine, dapsone or colchicine added and eye and renal review in the hypocomplementaemic form.

Where the exam tries to catch you

Three traps recur when urticaria is mislabelled as chronic urticaria.

Trap: labelling every long-lasting wheal as chronic idiopathic urticaria. Correct: a wheal lasting over 24 hours with burning and residual bruising points to urticarial vasculitis, which needs biopsy and complement testing.
Trap: expecting the usual response to antihistamines. Correct: antihistamines control urticarial vasculitis less well, so a poor response is itself a clue.
Trap: ignoring the lupus link in a woman with wheals and arthralgia. Correct: the hypocomplementaemic variant is linked with systemic lupus erythematosus, so antinuclear antibody and complement testing are needed.

Frequently asked questions

What is the key difference between urticarial vasculitis and ordinary urticaria?

Urticarial vasculitis wheals last longer than 24 hours, burn or ache, and leave residual bruising or pigmentation. Ordinary urticaria wheals are itchy, fade within 24 hours and leave no marks, which is the principal difference examiners test.

Why does hypocomplementaemia matter in urticarial vasculitis?

Low complement, particularly C1q, identifies the hypocomplementaemic urticarial vasculitis syndrome, which is more likely to affect the eyes, lungs and kidneys. Urticarial vasculitis with low complement is therefore linked with systemic lupus erythematosus and needs follow-up.

Which drugs treat urticarial vasculitis when antihistamines fail?

Hydroxychloroquine, dapsone, colchicine and systemic corticosteroids are commonly used when antihistamines fail to control urticarial vasculitis. Omalizumab has been reported to help refractory cases, and the choice depends on whether systemic disease is present.

Does urticarial vasculitis need a skin biopsy?

A skin biopsy is needed because it shows leukocytoclastic vasculitis, which separates urticarial vasculitis from ordinary urticaria. The biopsy is taken from a lesion that has persisted for a day or more, the very feature that defines the condition.