Urticaria and angioedema

Urticaria and angioedema are common hypersensitivity disorders characterized by recurrent episodes of transient wheals (hives) with or without deeper swelling of the skin and mucous membranes (angioedema). Urticaria results from the release of histamine and other inflammatory mediators from mast cells, leading to localized edema of the superficial skin. Angioedema involves deeper layers of the skin and subcutaneous tissues and commonly affects the lips, tongue, eyelids, and throat.

The condition may be acute (lasting less than 6 weeks) or chronic (persisting for more than 6 weeks). Chronic urticaria is frequently recurrent and may occur with or without an identifiable trigger. It is commonly associated with atopy and, in some cases, autoimmune disorders. Although most cases are self-limiting, angioedema involving the airway is a medical emergency because it can cause airway obstruction.

Pathophysiology

The main mechanism is mast cell activation, resulting in the release of histamine and other inflammatory mediators.

Common contributing factors include:

• Atopy (allergic tendency)

• Autoimmune disorders

• Food allergies

• Food additives and colourants

• Spices

• Medications (especially NSAIDs and antibiotics)

• Viral, bacterial, fungal, or parasitic infections

• Physical triggers such as pressure, heat, cold, sunlight, or exercise

• Emotional stress

Signs & Symptoms

Typical features include:

• Itchy wheals (hives)

• Wheals that disappear within 24 hours without leaving scars

• Recurrent episodes of skin rash

• Angioedema involving deeper tissues

Common sites of angioedema:

• Lips

• Tongue

• Eyelids

• Face

• Hands

• Feet

• Genitalia

Other findings:

• Swelling of the lips or tongue

• Burning sensation rather than itching in angioedema

• Symptoms may be precipitated by foods, spices, food colourants, medications, or infections

• Difficulty breathing or swallowing in severe cases due to airway involvement

Diagnostic criteria

Diagnosis is mainly clinical based on:

• Recurrent transient wheals lasting less than 24 hours

• Presence or absence of angioedema

• History of recurrent attacks

• Identification of possible triggering factors

Investigations

Most cases require only limited investigations. Further testing is recommended in chronic or recurrent disease.

Recommended tests

• Full blood picture (FBP)

• Erythrocyte sedimentation rate (ESR)

• Stool examination for ova and parasites

• Antinuclear antibody (ANA)

• Thyroid function tests

Allergy tests

• Skin prick test

• Patch test (when indicated)

Additional investigations may be performed depending on the suspected underlying cause.

Treatment

Treatment aims to relieve symptoms, prevent recurrence, identify and avoid triggers, and manage any underlying condition.

Non-pharmacological treatment

• Identify and avoid precipitating factors such as NSAIDs, foods, spices, and food colourants.

• Treat underlying infections appropriately, including bacterial, viral, fungal, or parasitic infections.

• Investigate for Helicobacter pylori infection when clinically suspected and treat according to gastrointestinal treatment guidelines.

• Deworm when indicated.

• Educate patients about recognizing triggers and avoiding recurrent exposure.

• Seek immediate medical attention if swelling affects the tongue, throat, or causes difficulty breathing.

Pharmacological Treatment

Antihistamine doses may be increased up to four times the standard dose for patients with chronic urticaria and continued for not less than 12 weeks when necessary.

• Step 1: A: cetirizine (PO) 10 mg once daily for 2–4 weeks (or loratadine 10 mg or desloratadine 5 mg once daily).

• Step 2: if not controlled, increase the antihistamine dose up to 4-fold, OR add D: montelukast (PO) 10 mg once daily for 4–8 weeks.

OR

• Loratadine (PO) 10 mg once daily; the dose may be increased up to fourfold if symptoms persist.

OR

• Desloratadine (PO) 5 mg once daily for not less than 16 weeks

AND

• Montelukast (PO) 10 mg once daily for not less than 16 weeks

Complications

• Recurrent chronic urticaria

• Persistent itching and sleep disturbance

• Reduced quality of life

• Anxiety and psychological distress

• Angioedema involving the airway

• Anaphylaxis (rare but life-threatening)

Prevention

Although not all cases can be prevented, recurrence may be reduced by:

• Avoiding known triggers

• Avoiding NSAIDs when they provoke symptoms

• Prompt treatment of underlying infections

• Avoiding foods or medications known to cause allergic reactions

• Adhering to prescribed treatment for chronic disease

• Regular follow-up in recurrent or difficult-to-control cases

Patient counselling (Important)

• Urticaria is not contagious.

• Individual episodes of wheals usually disappear within 24 hours, although new lesions may continue to appear.

• Chronic urticaria may persist for several months but is usually manageable with treatment.

• Avoid known triggers, including foods, medications, and spices that worsen symptoms.

• Take medications regularly as prescribed, even if symptoms improve.

• Seek emergency medical care immediately if swelling affects the tongue, throat, or causes difficulty breathing, as this may indicate a life-threatening airway obstruction.