GPAtlas🧭 When to suspect
Suspect urticaria when a patient presents with transient, intensely itchy, raised erythematous wheals (hives) that can appear anywhere on the body. The defining feature is timing: each individual wheal blanches, migrates and resolves within <24 hours leaving no mark, even though the overall eruption may come and go for weeks. It is frequently accompanied by angioedema – deeper, non-pitting swelling of skin or mucosa.
The key primary-care skills are to classify by duration and trigger, to recognise the dangerous mimics (urticarial vasculitis and bradykinin-mediated angioedema), and to remember that the great majority of long-lasting urticaria is not an allergy.
| Pattern | Defining feature |
|---|---|
| Acute urticaria | Wheals ± angioedema for <6 weeks; usually post-viral, drug-related or idiopathic, and typically self-limiting. |
| Chronic spontaneous urticaria (CSU) | Wheals on most days for ≥6 weeks with no consistent external trigger; frequently autoimmune; waxes and wanes over months to years. |
| Chronic inducible urticaria (CIndU) | Reproducibly provoked by a physical stimulus – dermographism, cold, heat, delayed pressure, cholinergic (sweating/exercise), solar or aquagenic. |
| Urticaria with angioedema | Deeper swelling of soft tissues (lips, eyelids, tongue) accompanying wheals; seen in up to ~40% of CSU. |
| Angioedema without wheals | Swelling alone – think ACE-inhibitor-induced or hereditary/acquired C1-inhibitor deficiency: a different, bradykinin-mediated pathway. |
|
🧠 Clinical pearl Treat angioedema without wheals as a separate disease. It is usually bradykinin-mediated, not histaminergic – so antihistamines, steroids and adrenaline are largely ineffective. ACE-inhibitor angioedema can appear months to years into stable therapy, and recurrent attacks without urticaria should prompt C1-inhibitor testing for hereditary angioedema. |
Source: British Association of Dermatologists · DermNet
🔒 Sign up free to read the full topic
You're viewing a free preview. Create a free account to unlock the rest.
Sign up free →Sample topics are open to everyone in the Free Sample Bundle.