Urticaria and Angioedema

A good history is essential. Concentrate on –


  • Whether child was well or ill before event (often triggered by a viral illness some time before)
  • Timing of onset / potential triggers (if food suspected, has to be within 2 hours of exposure and reproducible)
  • Appearance of rash (parents often take photo)
  • How long lesions lasted (usually < 24 hrs per lesion but can move around the body) 

Note that angioedema is often present with the urticaria but can (rarely) occur without urticaria. The swelling usually affects the lips, peri-orbital area and cheeks, ears but can, rarely, affect the airway 

Common causes that are not due to IgE – mediated allergy

  1. Chronic Spontaneous Urticaria (CSU) = classical urticarial rash on most days for > 6 weeks. ‘Idiopathic’ form common.

Affects 0.1 – 3% of UK children.

Usually starts with viral illness then Mast cells ‘primed’ and excitable, triggering rash at random times.

Can last 1 – 3 years.

Unlike in adults, cause rarely found 

  1. Physical urticarias eg heat, cold, pressure are often obvious from history and can be acute or chronic relapsing / remitting

 Management principles

  • Tests are rarely useful in CSU or physical urticarias
  • There are useful guidelines for management of chronic urticaria and angioedema on BSACI website at www.bsaci.org
  • First – line treatment is a non-sedating (second generation) antihistamine such as Cetirizine or Loratadine (licensed for > 2’s). Some children need trials of different antihistamines until find one that works best. Some need higher than recommended doses; these children can always be discussed.
  • Next step is a month’s trial of leukotriene receptor antagonist. If this is no help, refer.
  • Short courses (eg 3 days) of oral steroids can also help as a ‘one – off’ eg an important weekend away


Refer to Consultant – led Allergy clinic if –

-  Rapid development (< 2 hours) following exposure to food or latex

-  Symptoms suggesting angioedema of airway

-  A suspicion of C1 esterase inhibitor deficiency (rare, plaques of angioedema, airway swelling, no urticaria, not itchy, may be a family history)


Refer to General Paediatrics or Dermatology if –

- Troublesome, chronic urticaria not responding to trials of different antihistamines or monteleukast as per BSACI guidelines – culpable allergen unlikely

No need to refer if -

- Chronic Urticaria responding to treatment as above

- Short – lived, infrequent  episodes (<24 hrs), and no airway involvement (can often be attributed to viral infection and may recur intermittently)

Drug allergies

A drug allergy is defined as an immune-mediated hypersensitivity reaction to a medicinal product and may be divided into Immunoglobulin E (IgE) mediated (immediate-onset) reactions and non IgE-mediated (delayed-onset) reactions (RCPCH 2011).


A good history is essential, but recall for the historian can be difficult as time passes so the most detailed history needs to be taken on the first encounter with the patient / family after the event.

IgE – mediated allergic reactions are rapid in onset, much as they are for food.


In the case of Penicillin or other single antibiotic allergy, no need to refer if alternative antibiotics are tolerated.

 Please refer –

Any cases of anaphylaxis to a drug for consideration of a Consultant – led Allergy clinic appointment, or advice.

 Multiple antibiotic allergies from different classes of antibiotic for consideration of a Consultant – led Allergy clinic appointment, or advice.


 Guideline updated by Simon Bedwani, Consultant Paediatrician, Royal Cornwall Hospital, November 2018.


Date Reviewed                       14/08/2019

Date of Next Review              14/08/2020

GP Sifter                                 Dr Rebecca Harling


Version No.  1.1