The first time a parent sees urticaria — a child arriving at bedtime covered in raised welts that are migrating around the body — it looks like an emergency. Most of the time it is not. Most childhood urticaria is triggered by a viral illness, settles within a day or two on antihistamines, and never recurs in the same way. Knowing the pattern, knowing the difference between hives alone and hives with anaphylaxis features, and knowing that the food the child happened to eat earlier is rarely the cause saves a lot of unnecessary panic, food avoidance, and A&E visits. Healthbooq (healthbooq.com) covers allergy and skin conditions in children.
What Hives Look Like
Urticaria is the technical name for hives. The textbook features:
- Wheals — raised pale or pink centres surrounded by a red flare
- Itchy rather than painful
- Move around — appear in one place, fade within a few hours, appear elsewhere
- Individual welts last under 24 hours in the same spot, even though the rash overall may go on for days
- Can be anywhere on the body — face, trunk, arms, legs, sometimes the palms and soles
- Vary in size from a small coin to large patches that join up
A useful test: press a glass against the wheal. Hives blanch under pressure. The non-blanching petechial rash of meningococcal sepsis does not.
Angioedema is deeper swelling of the skin, often around lips, eyelids, hands, or feet. It can come with hives or alone. Angioedema with hives is usually allergic urticaria. Angioedema without hives, especially recurring or affecting throat or gut, may be hereditary angioedema and needs specialist input.
What Actually Causes Hives in Children
This is the biggest practical point in this article: in UK children, viral infection is by far the most common cause of acute hives, not food allergy. Studies put the proportion of acute paediatric urticaria caused by viruses at 60 to 80 per cent.
The classic story: a child has had a cold or a tummy bug for a couple of days, sometimes with a sore throat or a low fever, and then breaks out in hives. Often the child has been eating their normal foods. The parent assumes the lunchtime sandwich was the cause; in fact it was the virus.
Other causes:
- Specific food allergy — much less common than people assume in children. True food-allergic hives are consistent (same food causes it every time), often within minutes of eating, and usually accompanied by lip tingling, mouth itch, throat tightness, vomiting, or features of anaphylaxis. The major childhood allergens are peanuts, tree nuts, sesame, milk, egg, fish, shellfish.
- Bee or wasp stings.
- Medications — antibiotics (especially penicillins), NSAIDs, and others.
- Physical triggers — cold (cold urticaria), pressure, sweating from exercise, heat, water, sunlight.
- Contact — direct skin contact with plants, latex, animals.
- Idiopathic — sometimes no cause is identified.
For chronic urticaria (lasting more than six weeks, often daily), the picture is different: it is rarely allergic in children, and is most often chronic spontaneous urticaria — an autoimmune-flavoured condition that comes on without a specific external trigger and lasts months to years. It is annoying but not dangerous.
Why It Is Not Usually Food Allergy
Parents often connect urticaria with the most recent meal because the timing seems suggestive. The reasoning has several flaws:
- Children eat throughout the day; almost any rash will follow some food
- True food allergy almost always involves the same food causing the same reaction repeatedly
- Many "trigger" foods identified by parents stop being triggers when re-introduced under controlled conditions
- Acute viral urticaria typically resolves within a week regardless of food avoidance
Avoiding foods on the basis of one urticaria episode often leads to unnecessary dietary restriction, anxiety around eating, and (paradoxically) increased risk of subsequent allergy as the food disappears from the diet. The current evidence — particularly the LEAP study and follow-on work — supports continued ordinary eating of common allergens, not avoidance, as the safest course unless there is clear allergy evidence.
If you suspect a specific food, see the GP. Allergy testing (skin prick testing, specific IgE blood testing) by a paediatric allergy team can clarify, and structured food challenges can confirm or refute. Cutting foods out without this is rarely the right move.
Treatment
First-line: non-sedating antihistamine. Cetirizine or loratadine (sometimes fexofenadine) at the appropriate paediatric dose.
- Cetirizine syrup is widely used; standard age-appropriate doses are on the bottle and on the NHS website. Often given once or twice a day during an episode.
- Loratadine similarly available; once-daily dosing.
These can be given at standard doses; for stubborn urticaria, allergy specialists sometimes use up to 4× the standard dose under their guidance.
Sedating antihistamines (chlorphenamine, "Piriton") are less preferred for routine daytime use — they make children drowsy and impair school function — but are sometimes useful for night-time itch interfering with sleep.
Oral steroids (prednisolone) are reserved for severe or extensive acute urticaria where the child is significantly distressed, particularly with angioedema affecting the face. Used as a short course, prescribed by GP or A&E.
Cold compresses, loose clothing, lukewarm baths — settle the itch. Avoid heat and prolonged hot water, which often make hives worse.
Avoid the trigger if known. For viral urticaria, this is not relevant. For specific allergies, yes. For physical urticarias (cold, pressure, exercise), modify exposure plus antihistamine prophylaxis.
When Hives Are Part of Anaphylaxis (Different Picture)
Hives alone, in a child who is otherwise well, alert, breathing normally, and engaged, are not an emergency. Antihistamines and watching is the right approach.
Hives plus any of the following — call 999 and use an EpiPen if available:
- Difficulty breathing, wheeze, persistent cough
- Throat tightness or hoarse voice
- Tongue or lip swelling that is rapidly progressing
- Persistent vomiting, severe abdominal pain
- Pale, mottled, floppy, or collapsed
- Drowsy, confused, or unresponsive
- Two or more body systems affected at once
Anaphylaxis is the medical emergency. Antihistamines do not stop anaphylaxis — adrenaline does, given as soon as anaphylaxis is recognised. The Resuscitation Council UK and Allergy UK both publish clear action plans for families with adrenaline auto-injectors.
If a child has had one episode of anaphylaxis, they need a written allergy action plan, an adrenaline auto-injector, and ideally referral to a paediatric allergy clinic.
Cold Urticaria — Worth a Specific Mention
Some children develop hives within minutes of skin contact with cold — cold air, cold water, an ice cream, even a cold bench. This is cold urticaria, treatable with daily antihistamines and significant because cold water immersion (e.g. swimming in a pool, the sea, a cold bath) can trigger systemic reactions including hypotension and collapse. Children with cold urticaria should not swim alone, particularly in open water, and benefit from specialist allergy assessment.
Chronic Spontaneous Urticaria
Hives daily or near-daily for more than six weeks without an identifiable trigger. About 0.1–0.5% of children. Frustrating and itchy but rarely dangerous. Management:
- Daily non-sedating antihistamine, sometimes at higher than standard dose under specialist guidance
- Omalizumab (anti-IgE injection) for cases not responding to high-dose antihistamines — usually under paediatric allergy or dermatology
- Cyclosporin in some cases
- Most resolve over months to a few years
Children with chronic urticaria benefit from a paediatric allergy or dermatology referral.
When To Seek Medical Help
A GP appointment for hives if:
- You're not sure what is happening
- The hives have lasted more than a couple of days despite antihistamines
- They keep recurring
- The child is uncomfortable or sleep-disturbed
- There's any uncertainty about whether the trigger is food
Same-day GP, NHS 111, or A&E if:
- Significant facial swelling
- Hives plus the child seems unwell
- Hives following a known allergen the child has reacted to before
- You're not sure but the child looks worse than before
999 / A&E now if:
- Difficulty breathing, throat tightness, wheeze
- Tongue/lip swelling progressing
- Drowsy, floppy, pale, mottled
- Collapse
- Use the adrenaline auto-injector first if available
Practical Things at Home
- Keep cetirizine or loratadine in the medicine cupboard — useful for any future episode
- Cool the child down — fan, light cotton clothing, lukewarm baths
- Avoid the things that worsen itch — hot showers, woolly clothes, scratchy fabrics
- Photograph the rash — useful for the GP and for tracking patterns
- Keep a diary if hives are recurrent — what was eaten, what activities, what virus was around
- Don't restrict food without allergy evidence — see the GP first
A Reassuring Long View
Most childhood urticaria is a one-off following a viral illness. It looks dramatic, settles with antihistamines, and never returns. A smaller number of children develop ongoing or chronic urticaria, which is manageable with daily medication and occasional specialist input. A small minority have urticaria as part of a true food allergy, which deserves diagnosis, planning, and treatment. Knowing the difference is the parent's main job; the rest is an antihistamine and a quiet evening.
Key Takeaways
Hives that appear, move, and disappear are usually triggered by a viral illness, not by food. Cetirizine or loratadine handles most episodes. The thing to recognise is the difference between hives alone (not an emergency) and hives plus throat tightness, breathing difficulty, wheeze, or collapse — that is anaphylaxis and needs an EpiPen and 999.
