In short
Hives are itchy raised welts that appear suddenly, shift around and fade within a day. Most bouts settle on their own, but knowing the difference between hives and an allergic emergency — and what 'chronic' hives usually mean — matters.
Emergency if: Hives with swelling of the tongue or throat, difficulty breathing, wheeze, faintness or collapse — this is anaphylaxis: use an adrenaline auto-injector if available and call emergency services.
On your report
Total IgE, Absolute Eosinophil Count, TSH, Anti-TPO Antibodies +2 more
On this page
01
Recognising Hives
Urticaria appears as raised, pale-to-pink welts (wheals) with a surrounding flare, ranging from a few millimetres to the size of a hand, and usually intensely itchy. The giveaway is that individual welts move: each one fades within 24 hours without leaving a mark, while new ones may appear elsewhere. Pressing a welt makes it blanch.
Roughly 4 in 10 people with chronic hives also get angioedema — deeper swelling of the lips, eyelids, hands or feet — which is uncomfortable but not dangerous unless it involves the tongue or throat.
02
Acute Hives: the Usual Triggers
A bout lasting under six weeks is 'acute'. Often no trigger is ever identified; among those that are, infections — typically a viral cold or stomach bug in the preceding days — are the most common, especially in children. Other causes include foods (nuts, shellfish, eggs, milk in children), medicines (antibiotics, NSAIDs like ibuprofen, some blood pressure drugs), insect stings, latex and contact with plants or animals.
Physical triggers deserve a mention: pressure, cold, heat, sunlight, exercise and even scratching (dermographism) can provoke hives in some people. Often no cause is found at all, and the bout simply runs its course over days to a couple of weeks.
03
Chronic Hives Are Rarely an Allergy
Hives that recur most days for longer than six weeks are 'chronic'. This is where expectations often go wrong: chronic urticaria is almost never caused by a hidden food allergy, and extensive allergy testing is generally unhelpful. In up to half of cases the immune system is producing antibodies that activate the skin's mast cells directly — an autoimmune mechanism, sometimes accompanied by thyroid autoimmunity.
Doctors usually check a full blood count, ESR or CRP and thyroid function (including thyroid antibodies) to look for associated conditions, but the diagnosis rests on the history. Stress, heat, tight clothing, alcohol and NSAIDs commonly worsen chronic hives without being the underlying cause.
04
Treatment That Works
Non-drowsy antihistamines (cetirizine, loratadine, fexofenadine) are first-line for both acute and chronic hives. For chronic urticaria, guidelines allow the dose to be increased up to four times the standard amount under medical advice before moving on; many people are under-treated at a single daily tablet. Older sedating antihistamines add little except drowsiness.
A short course of oral steroids is sometimes used for a severe acute flare but is not a long-term treatment. For chronic hives that don't respond to high-dose antihistamines, the injectable antibody omalizumab is highly effective. Chronic urticaria usually burns out on its own: about half of people are clear within a year, though for some it persists for several years.
05
Hives Versus Anaphylaxis
Hives alone, however widespread and itchy, are not anaphylaxis. The emergency picture is hives or flushing together with difficulty breathing, wheeze, throat tightness, a hoarse voice, faintness or collapse, or persistent vomiting — usually within minutes to an hour of a food, sting or medicine. That combination needs an adrenaline auto-injector if one is available and an emergency call.
After any suspected anaphylaxis, referral to an allergy clinic is essential to identify the trigger and prescribe adrenaline for the future.
When to act
Emergency — act now
Hives with swelling of the tongue or throat, difficulty breathing, wheeze, faintness or collapse — this is anaphylaxis: use an adrenaline auto-injector if available and call emergency services.
Same-day — call promptly
Hives starting within an hour of a new medicine, food or sting, or facial swelling that is spreading.
Routine — see a doctor
Hives recurring for more than six weeks, or a bout not settling with over-the-counter antihistamines.
Values mentioned in this story
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Sources
- Hives — MedlinePlusmedlineplus.gov
- Hives (urticaria) — NHSnhs.uk
- Urticaria — DermNetdermnetnz.org
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