When is urticaria serious?

Written by: Professor George Du Toit
Published:
Edited by: Nicholas Howley

Urticaria, also known as hives, is common in childhood. Allergic hives are usually short lived, but allergic reactions can be severe (anaphylaxis). Hives that arise due to an infection can persist for many days and will go away on its own. In rare cases, urticaria can be chronic (lasting longer than 6 weeks), and more specialist treatment might be necessary.

In this article, paediatric allergist Professor George Du Toit gives an overview of the different types of urticaria, what to expect, and what treatment looks like. The terms urticaria/hives/wheals are used interchangeably.

Allergic hives

The commonest cause of urticaria is a food allergy, where the child typically develops skin rashes and hives after eating an allergic food. Given the obvious causality between symptoms and food ingestion and the rapid onset of symptoms, this is generally an easy diagnosis to make. The child will often dislike food and is unlikely to eat it on recurrent occasions. Hives that arise due to a food allergy are usually short lived (hours) and associated with other allergy symptoms such as behavioural change, vomiting, gut pain, or intra-oral symptoms such as a tickly throat.

Non-allergic hives

Children may develop hives after an infection. The child may not be that unwell at the time of the causal infection which may have been something as simple as a seasonal cold and are seldom unwell when the hives first begin. Whilst these hives are often very angry-looking and make the child uncomfortable as they are extremely itchy, children come to no harm, as they are not associated in any way with severe allergic reactions. Antihistamines are only partially successful at providing total symptom control. The hives, which may be large and generalised in distribution, will resolve on their own. There is no need for treatment of the underlying infection if the child is otherwise well.

Spontaneous Chronic urticaria (CU)

Chronic urticaria is where the hives persist for at least six weeks, and is more troubling.

In CU the hives are flitting and will wax and wane in intensity and, in children, are usually associated with angioedema (swelling of the lips or eyelids).

CU is generally considered an autoimmune condition, where the body raises antibodies against the cells that release histamine in the skin and mucosal tissues (mast cells and basophils). CU is more difficult to treat and high-dose antihistamines will frequently be required. If they’re not sufficient, then in specialist care setting, more advanced add-on medications can be recommended. Food allergy is seldom ever a cause of CU. It may take many years before CU is spontaneously outgrown.

Physical urticaria

There are many physical triggers for chronic urticaria. These triggers can be cold, vibration, or pressure-induced. For example, where a child is held firmly, their skin may develop hives, or scratch marks may induce linear streaks (known as dermatographism). In cold urticaria hives will come on in exposed areas, particularly after rapid temperature fluxes. Heat may also do this, as may ultraviolet light. This is known as solar urticaria. It is very rare for other triggers such as water to cause inducible hives, but there are conditions known as aquagenic urticaria. In older children at the time of exercise they may develop a variant of hives known as cholinergic urticaria. Children with CU usually have hives that are exacerbated by one or more physical triggers.

The goal of therapy in chronic urticaria is to treat the disease until all symptoms remit – with as few side effects of the treatment as possible.

By Professor George Du Toit
Paediatric allergy & immunology

Professor George Du Toit is a consultant paediatrician with more than two decades of experience treating and managing patients with complex allergies such as eczema, food allergy, asthma, antibiotic allergy and hayfever. His team aim to provide patient-centered and responsive care, backed by the highest safety standards and are supported by an experienced team of Nurses, Psychologists, Dietitians and Practice Management staff.

Professor Du Toit loves his chosen niche of paediatric medicine and this is reflected in his excellent patient/family feedback. Professor Du Toit holds private clinics at the Portland Hospital, Great Ormond Street Hospital and in New Malden, Surrey; his NHS practice is at the Evelina Children's Hospital, London.

Professor Du Toit is one of the Directors of The Food Allergy Immunotherapy Centre (TFAIC) based at GOSH. This service provides desensitisation for peanut (using Palforzia) as well as other food allergies (cashew and sesame commencing 2023). Professor Du Toit oversees Oral Food Challenge tests for the diagnosis of food allergy at the TFAIC, and The Portland Hospital.

Professor Du Toit is renowned for his clinical research, having conducted landmark trials into the prevention and treatment of food allergies. He has served as Investigator on trials that have led to the licensing of Palforzia, and the development of the EPIT peanut patch.

Recent prestigious international awards include the Hugh A. Sampson Lectureship in Food Allergy at the 2022 AAAAI Annual Meeting, the UK Dept Health and Social Care Advisory Committee on Clinical Excellence Awards (ACCEA) Bronze award in 2021, the Daniel Bovet Award for Allergy Treatment and Prevention by the European Association of Allergy and Clinical Immunology in 2020 and the Dr William Frankland Award for Outstanding Contribution to Allergy by the British Society of Allergy & Clinical Immunology in 2020. 

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