Hives: common allergy triggers
Raised, itchy welts that appear, move around and fade within hours are hives. Sometimes they follow a specific food, sting or contact. Often they do not. Our test measures IgE sensitisation to 300 allergens and allergen components, which helps when you suspect a trigger and want to check it.
What hives are
Hives, or urticaria, are raised patches of skin, pale in the middle and red around the edge, that itch or burn. Each welt usually fades within 24 hours, while new ones may appear elsewhere. They happen when mast cells in the skin release histamine.
Hives can come with swelling deeper in the skin, often around the lips, eyes or hands. That is called angioedema. If swelling affects the tongue or throat, or comes with breathing trouble, it is an emergency.
Acute hives and allergens
Hives that appear suddenly and clear within days or weeks are called acute. When an allergen is involved, the timing is usually tight: welts within minutes to about two hours of eating a food, being stung, or touching something like latex or an animal.
- Foods: peanut, tree nuts such as hazelnut, egg, milk, fish, shellfish, wheat and soy.
- Insect stings: wasp and bee venom.
- Contact: latex gloves or balloons, cat or dog saliva on skin, horse hair.
Chronic hives are usually not allergic
Hives that come and go on most days for more than six weeks are called chronic urticaria. In most cases no external allergen is found; the immune system triggers the mast cells itself. Infections, heat, pressure, exercise, stress and some medicines such as ibuprofen can also play a part.
That is worth knowing before you test. If your hives are chronic and not linked to anything you ate or touched, a long list of sensitisations is unlikely to explain them, and a doctor or dermatologist is the better first step.
What the test shows
If your hives follow a pattern, the test checks IgE to 300 allergens and allergen components, including the major foods, venoms, animals and latex. Each gets a measured value and class, from Negative to Very high, so you can see whether a suspected trigger shows up.
A positive result means sensitisation, not proof of cause. Plenty of people carry IgE to foods they eat without any problem. Do not cut foods from your diet based on the results alone; discuss them with a doctor first, especially for a child.
When to see a doctor first
Call 112 or your local emergency number if hives come with swelling of the tongue or throat, trouble breathing or swallowing, dizziness or fainting. See a doctor if hives last more than a few days, keep coming back, follow an insect sting, or appear in a young child.
Allergens often linked to this
Related symptoms
300 allergens. One test.
A finger-prick sample at home, sent by post. A detailed lab report typically 5 days after the lab receives your sample, and our plain-English guide to reading it. €300, €1 per allergen.
Questions
Can an allergy test find the cause of chronic hives?
Usually not. Most chronic hives, lasting more than six weeks, have no external allergen behind them. An IgE test is most useful when hives follow something specific, like a food or a sting.
How quickly do allergic hives appear after eating?
IgE-mediated reactions typically start within minutes and up to about two hours after eating. Hives that appear the next day are less likely to be caused by a food allergy.
My result shows a reaction to a food I eat every day. Should I stop?
Not without talking to a doctor. Sensitisation without symptoms is common, and unnecessary avoidance can do more harm than good, particularly in children.
Are hives dangerous?
Hives on their own are uncomfortable but usually not dangerous. They become urgent when they come with swelling of the face, tongue or throat, breathing trouble or feeling faint. Then call emergency services.