Chronic hives (chronic urticaria) are itchy, raised welts that keep appearing for more than six weeks. In most people, no single allergy is to blame. Flares are often set off or made worse by heat, pressure on the skin, stress, infections, alcohol and some painkillers. See a dermatologist if hives keep returning, as treatment can usually bring them under good control.
Key takeaways
- Hives are called chronic when they come and go for longer than six weeks.
- Most chronic hives are "spontaneous", meaning they appear without a clear outside cause, and are often linked to the immune system rather than a food allergy.
- Some chronic hives are "inducible", triggered by a physical factor such as scratching, pressure, heat, sweating, cold or sunlight.
- Keeping a simple symptom diary is one of the most useful things you can do before seeing a doctor.
- Swelling of the lips, tongue or throat with difficulty breathing is an emergency: call 995.
What is chronic urticaria?
Urticaria is the medical name for hives: raised, itchy, red or skin-coloured welts (wheals) that appear suddenly. Each individual wheal usually fades within 24 hours without leaving a mark, but new ones may appear elsewhere.
When hives come and go for less than six weeks, they are called acute urticaria. When they keep returning for more than six weeks, they are called chronic urticaria. Some people also get angioedema, which is deeper swelling of the skin, often around the eyes, lips, hands or feet.
Our urticaria (hives) condition page covers the condition and treatment options in more detail. This article focuses on what triggers chronic hives and when to seek help.
What are the types of chronic hives?
Chronic hives fall into two broad groups. Knowing which type you have helps your doctor decide which tests, if any, are needed.
Type | What it means | Examples |
|---|---|---|
Chronic spontaneous urticaria | Hives appear on their own, with no consistent outside trigger | Wheals that turn up at random times, often worse in the evening |
Chronic inducible urticaria | Hives are set off by a specific physical trigger | Scratching, pressure, heat, sweating, cold, sunlight or water |
Some people have both types at once. Chronic spontaneous urticaria is thought to involve the immune system reacting against the body’s own mast cells (cells in the skin that release histamine, the chemical that causes itching and swelling).
What triggers chronic hives?
For chronic spontaneous urticaria, there is often no single root cause, but several things can make flares more likely or more severe. For inducible urticaria, the trigger is usually a physical one that you can learn to recognise.
Physical triggers (inducible urticaria):
Scratching or rubbing:
Firm stroking of the skin leaves raised lines, known as dermographism or "skin writing".
Pressure:
Tight waistbands, bra straps, bag straps or sitting for long periods can cause swelling hours later.
Heat, sweat and exercise:
Small, very itchy bumps after a hot shower, exercise, spicy food or emotional stress (cholinergic urticaria). This is easy to notice in Singapore's climate.
Cold:
Air-conditioned rooms, cold drinks or swimming in cool water can trigger wheals.
Sunlight:
hives on sun-exposed skin within minutes of being outdoors.
Things that can make any chronic hives worse:
- Anti-inflammatory painkillers such as aspirin and ibuprofen
- Alcohol
- Viral infections, such as a cold
- Emotional stress and poor sleep
- Heat and tight clothing
Food allergy is a much less common cause of chronic hives than many people expect. A true food allergy usually causes a reaction within minutes to a couple of hours of eating that food, every time, rather than hives most days for months.
How can you find your triggers?
A symptom diary is the simplest way to spot patterns. Record your hives for two to four weeks before your appointment and bring the notes with you.
- Take photos of the hives when they appear, as they may have faded by the time you see a doctor.
- Note the time they appeared and how long each wheal lasted.
- Write down what you were doing: exercise, hot shower, air-conditioning, tight clothing, sun exposure.
- List any medicines taken in the past few days, including painkillers and supplements.
- Record what you ate and drank, including alcohol, but avoid cutting out whole food groups without advice.
- Note other factors such as a recent cold, stress, poor sleep or your menstrual cycle.
How are chronic hives managed?
Most people with chronic hives can get good control with the right treatment, although the condition may take months or years to settle on its own. A dermatologist will tailor the plan to your type of urticaria and how much it affects your life.
Management usually involves:
- Avoiding known triggers where practical, such as loosening tight clothing or avoiding certain painkillers.
- Daily non-drowsy antihistamines, taken regularly rather than only when hives appear. Your doctor may adjust the dose.
- Further options for hives that do not respond, which can include an injectable biologic treatment that targets part of the allergic pathway. Your dermatologist will explain whether this suits you.
Tests are not always needed. For chronic spontaneous urticaria, doctors usually limit tests to a few basic blood tests unless your history points to something specific. Allergy testing is not routinely helpful unless there is a clear link to a food, medicine or contact.
When should you see a dermatologist about hives?
See a dermatologist if your hives have lasted more than six weeks, keep coming back, disturb your sleep or work, or are not controlled with over-the-counter antihistamines. It is also worth seeing a doctor if you are not sure whether your rash is hives at all.
See a doctor sooner if:
- Individual wheals last longer than 24 hours, leave bruising or marks, or burn rather than itch
- You have fever, joint pain or feel generally unwell along with the hives
- You get frequent swelling of the lips, eyelids or hands
Call 995 or go to the emergency department if hives come with swelling of the tongue or throat, difficulty breathing or swallowing, wheezing, dizziness or fainting. These can be signs of anaphylaxis, a severe allergic reaction.
If it is your first visit, our guide to your first dermatology appointment in Singapore explains what to expect. People with hives often have other sensitive-skin concerns too; our article on managing sensitive skin has practical tips.
Frequently asked questions
Are chronic hives an allergy?
Usually not in the traditional sense. Most chronic hives are spontaneous and linked to the immune system reacting in the skin, rather than to a specific food or substance. That is why allergy tests often come back normal in people with chronic hives.
Can stress cause hives?
Stress does not usually start chronic hives on its own, but it is a common reason for flares. Poor sleep, busy periods at work and illness can all make hives worse. Managing stress and sleep can help alongside medical treatment.
Are chronic hives contagious?
No. Hives cannot be passed from one person to another. They are a reaction happening within your own skin.
Will chronic hives ever go away?
In many people, chronic spontaneous urticaria settles on its own over time, often within a few years, though it can last longer. While you wait for it to settle, treatment aims to keep you comfortable and free of hives.
How are hives different from eczema?
Hives are raised welts that move around and each one fades within a day. Atopic eczema causes dry, rough, itchy patches that stay in the same areas, often in skin creases. A dermatologist can tell them apart.
This article is for general information only and is not a substitute for medical advice. Please consult a qualified doctor or accredited dermatologist doctor in Singapore for advice specific to your situation.