Hives is a common rash, which is characterised by pink or white raised areas of the skin. These areas are usually itchy and circular-shaped. In most cases they’re self-limiting and will disappear within a short time, but can sometimes be a sign of a serious allergic reaction.
- Around 20% of people will experience hives at some point
- Can be caused by an allergic reaction to food, medicine or a bite
- Rash will disappear on its own but treatment can ease symptoms
If you would like to speak to one of our GMC-registered clinicians about hives, you can do so using our online video consultation service. Book an appointment at a time that suits you, between 9.30am and 4.30pm, five days a week.
What causes hives?
Hives or urticaria (also known as nettle rash) is caused by a very small amount of fluid called histamine being released in the body. Histamine is linked to our body’s defences, and is released in response to what the body perceives as a threatening, harmful substance. It causes the characteristic bumps seen in hives, and the blood vessels to widen, which in turn results in inflammation.
There are many possible triggers for hives. Physical stimulus, such as sweat from exercise, or a change in climate that exposes the body to hot or cold air suddenly, can cause it. This is more common in cases of chronic hives, where the rash can last for up to six weeks.
An allergic reaction may also lead to hives. This can stem from eating or coming into contact with food such as nuts or shellfish, or being stung by a bee or a wasp. Medicines can trigger this reaction too as a side effect. Penicillin, painkillers (aspirin and ibuprofen) and vaccinations are among the treatments most likely to lead to a breakout of hives.
Hives can also occur as a result of the body reacting to a viral infection (which causes histamine release), or stress.
Symptoms of hives
Hives can either be acute or chronic. Acute hives lasts less than six weeks and usually resolves within a couple of days. Some allergic reactions may last for only a few hours. Chronic hives however lasts for longer than six weeks.
The main symptom of hives is an itchy rash, which can occur anywhere on the body. It forms slightly raised patches of inflamed skin called weals. They are usually no more than a few centimetres in size. When the weals begin to fade, usually within a couple of days, the surrounding area will remain blotchy and red for a short while longer before healing and returning to normal.
Despite the potentially severe itching associated with hives, it is thought that the rash has no long-term effect on a person’s health.
Hives can develop as part of a severe allergic reaction (anaphylaxis). In such cases, the rash will often be accompanied by difficulty breathing, dizziness, a severe drop in blood pressure, and noticeable swelling of the face, lips or throat. This will require an adrenaline pen to be administered, and emergency treatment at a hospital.
Hives is normally quite easy to identify.
A diagnosis can be made by a physical examination, and in most cases you will be aware of what has led to them. Your doctor may ask you about any recent changes you have made to your diet, whether you’re taking new medication, if you have been stung by an insect, or if you have changed your hygiene routine (for example, changed detergents).
If hives is recurrent, a doctor may recommend using a symptom diary, so that you can try to find out what the cause is. For example, if you notice the rash after eating certain foods, or having been exposed to sunlight or after exercising.
A doctor can also perform some tests if necessary, although this is not usually required. Skin-prick allergy tests can be helpful in investigating what the allergy may be, and involves putting a very small amount of the potential allergen on the skin to see how the skin reacts. Blood tests can also be helpful to establish if the body is producing antibodies as an autoimmune response, which causes the rash. Furthermore, a biopsy can be taken where a small section of skin is removed to be examined in a laboratory.
What you can do to help hives
It’s important to avoid any known triggers, be it pollen, certain foods or chemicals, or stress.
There are several factors that may exacerbate hives and should be avoided even if they are not direct triggers. You should not wear tight fitting clothing around the skin where hives is present, and allow the skin to stay cool and dry where possible. Drinking alcohol, exposing the rash to direct sunlight, and bathing in hot water can all contribute towards making the symptoms worse.
How is hives treated?
Antihistamine medicines can help with hives as they limit the activity of histamine in the body. The most common antihistamines currently used for hives are cetirizine, fexofenadine and loratadine. They can be purchased without a prescription from a pharmacy, but if they are being used extensively at a higher dose, a prescription from a doctor will be needed.
Antihistamines can cause drowsiness, although this is uncommon in a non-prescription dose. Chlorpheniramine and hydroxyzine are two antihistamines which are supposed to be taken before you go to bed, and can be useful if itching is preventing someone from sleeping.
For severe symptoms, a doctor may recommend treating hives with corticosteroids. These drugs work by suppressing the immune system. For example, prednisolone can be prescribed for hives, but it should not be taken for more than three to five days for this purpose, as complications can occur with extended use.
If someone is diagnosed with chronic hives, then antihistamines will need to be prescribed for a much longer period of time, until the condition of the skin improves.
You should see a doctor about alternative treatment if your current course of medication is having an impact on your hives.
If you are concerned about hives, our clinicians are available to speak to online via our video consultation service. Our clinicians can discuss your symptoms and treatment options, and provide prescriptions and referrals to specialists, where required. You can book an appointment between 9.30am and 4.30pm, Monday to Friday.
How long is it normal to have hives for?
Hives usually lasts for no longer than 48 hours, but it can last for up to six weeks. Chronic hives is when symptoms last for longer than 6 weeks.
If hives is persistent, it may occur in episodes over an extended period. It’s important to try and identify what the triggers are and avoid them where possible.
Is hives serious?
Not usually. It often disappears within a few hours or a couple of days.
There are some cases however where it can be serious and these are usually where it’s related to a severe allergy. If someone has a severe reaction to peanuts or a bee sting for example, they may go into anaphylactic shock, and hives can be symptomatic of this.
If you experience a severe allergic reaction, you may also notice swelling in the face or throat, or difficulty breathing. This constitutes a medical emergency, and you should be seen in hospital as soon as possible.
Can I get treatment for hives?
Hives doesn’t always require treatment, as it will often subside on its own.
If symptoms are causing irritation or discomfort, antihistamine medicine or corticosteroids may be recommended.
How can I prevent hives?
Hives cannot always be prevented, as some triggers are unavoidable. However, if you know that your symptoms are exacerbated by factors such as caffeine, alcohol, or sweating, you should try to avoid them.
To help you identify what the trigger is for hives, it can be helpful to keep an activity or food diary.
Can I speak to a doctor about hives online?
Yes. You can book an appointment with one of our clinicians using our online video consultation service, between 9.30am and 4.30pm, Monday to Friday. Our GPhC-registered doctors can issue advice about managing hives and let you know whether you will need further treatment. They can also issue prescriptions and referrals to specialists for treatment, where appropriate.