Hives (urticaria) are raised red welts or raised patches that itch intensely. Their hallmark is that they "appear quickly and fade quickly" — each spot usually lasts only a few hours then fades without leaving a mark, but can reappear in another location, which is why it is a rash that comes and goes. They occur when the body releases substances that make the surface blood vessels leak and swell into welts.
Signs of a severe allergic reaction — go to hospital immediately
If hives occur together with these symptoms, it is a severe allergic reaction (anaphylaxis) that is life-threatening. Go to a hospital or call an ambulance immediately.
- Difficulty breathing, chest tightness, or wheezing
- Swelling of the face, lips, tongue, or throat, difficulty swallowing, or a hoarse voice
- Severe dizziness, faintness, fainting, or palpitations
- Nausea, vomiting, or severe abdominal pain together with a rapidly appearing rash
What causes hives?
Hives have many possible triggers, and sometimes no clear cause can be found. The most common triggers include:
- Food allergies, such as seafood, nuts, eggs, milk, or certain additives
- Certain medications, such as painkillers and antibiotics
- Insect bites and stings, and contact with allergens
- Hot or cold weather, sweat, stress, or infection — and in some people, no known cause
Care and treatment
For ordinary hives without a severe allergic reaction, care focuses on relieving the itch and avoiding triggers.
- Avoid the suspected triggers, and keep a record of what you ate or were exposed to before the rash
- Take antihistamines as your doctor advises to reduce the rash and itching
- Avoid heat and scratching, and wear loose, comfortable clothing
Acute and chronic hives
Acute hives usually go away on their own within a few days to weeks, while chronic hives come and go for more than 6 weeks and are usually well controlled with antihistamines at the dose the doctor adjusts. Seeing a doctor helps you get a suitable treatment plan and look for any underlying cause.
Prevention
Once you know what you are allergic to, you should avoid it strictly, and always tell your doctor and pharmacist about your drug and food allergy history. People who have had a severe allergic reaction should discuss being prepared to manage it with their doctor. Keeping a record and watching for triggers helps reduce the chance of hives recurring.
At Doctor Chat Clinic, we examine and treat skin conditions including hives, with care by a doctor — helping to assess your symptoms, look for triggers, and provide suitable antihistamines, along with advice on self-care and watching for warning signs.