Hives can appear and disappear quickly, with each hive only lasting around 2–3 hours. However, depending on the cause, they may reappear and continue affecting someone for days, weeks, or longer.

People can have acute hives, which occurs due to a specific trigger and resolves within 6 weeks. Alternatively, they can have chronic hives, which recur at least twice per week for longer than 6 weeks.

This article looks at how long hives last, factors that influence their duration, and treatment.

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Each hive lasts only 2–3 hours, but for some people, they continue to appear and disappear for longer. The duration of hives can depend on whether they are acute or chronic.

Acute hives appear quickly and do not last long. Doctors classify hives as acute if the overall duration is less than 6 weeks.

However, around 25% of people go on to develop chronic hives. This is when hives regularly reappear over 6 weeks or more.

For many individuals, chronic hives eventually clear on their own, but this can take months. According to the American Academy of Dermatology Association (AAD), around half of people with chronic hives spontaneously recover within 1 year.

Acute hives often occur in response to an allergen or irritant. When the immune system perceives a substance as a threat, it releases histamine and other chemicals. This causes tiny blood vessels under someone’s skin to leak fluid, which accumulates and causes the bump.

Some common substances that can result in hives include:

  • food allergens, such as milk, eggs, tree nuts, peanuts, or shellfish
  • contact allergens, such as latex or animal dander
  • insect bites or stings
  • medications

Any drug can cause hives, but some of the medications most commonly associated with this symptom include:

Acute hives can also occur in response to viral infections, parasitic infections, or during times of stress.

According to a 2018 review, doctors are unsure of the cause of acute hives in around 50% of individuals. These cases are known as acute spontaneous urticaria (ASU).

Chronic hives may have the same cause as acute hives, but with symptoms lasting longer than 6 weeks. However, chronic hives are often not due to an allergen and instead have a physical cause.

There are two subcategories of chronic hives: inducible urticaria and chronic idiopathic urticaria.

Chronic idiopathic hives

Chronic idiopathic urticaria has no clear cause and is the most common form of chronic hives. Researchers are working to understand why this type of hives occurs, but a leading theory links it with autoimmunity.

Autoimmunity occurs when a person’s immune system mistakenly attacks healthy tissue, and several autoimmune conditions are associated with chronic hives. The most common is thyroid disease, which is present in 9.8% of cases.

This suggests that the hives may result from someone’s immune system not functioning as it should. Other conditions that can occur alongside chronic hives include type 1 diabetes, lupus, and rheumatoid arthritis.

Infections can also be associated with the onset of chronic hives. This includes bacterial, viral, and parasitic infections. Again, this may result from autoimmunity — an infection may trigger a change in how the person’s immune system works.

Inducible hives

Inducible or physical urticaria is less common than chronic idiopathic urticaria. With this subtype, it is possible to purposely induce the hives by a person exposing their skin to certain triggers, which could include:

  • Scratching or pressure: The most common type of inducible hives is known as dermatographia. This condition involves developing hives as a response to scratching or “drawing” on the skin.
  • Cold: Cold hives occur on someone’s skin or mouth after exposure to cold temperatures. Triggers include consuming iced drinks, touching cold water, or going outside in cold weather.
  • Heat: Cholinergic hives occurs when an individual’s body becomes hot or sweaty. Hot baths, exercise, and spicy food can be triggers.
  • UV light: Solar hives occur in response to UV light from the sun and certain light bulbs, such as those in tanning beds.
  • Water: Some people develop hives if their skin comes into contact with water. This is known as aquagenic urticaria and is very rare.

Doctors diagnose hives by performing a physical examination. There is no test to determine whether the person’s hives are acute or chronic, so they will use the length of time they recur to do this.

The doctor may also ask an individual:

  • when the rash began
  • the shape, size, and distribution of the rash
  • where on the body they first noticed the rash
  • if they have had any insect bites
  • if they live or work with common hive triggers, such as chemicals, animals, or latex gloves
  • if they have bone or joint pain, fever, or abdominal pain
  • if anyone in their family experiences hives
  • if they take any medications or supplements

The doctor may use a skin prick test and serum-specific IgE test to check if the acute hives result from a specific substance, such as food, dust mites, or chemicals. Alternatively, they may refer someone to an allergy clinic for these tests.

However, in cases of chronic hives, allergy testing is rarely useful. A doctor may check for other underlying health conditions by performing additional tests, such as:

The most suitable treatment depends on whether the person has acute hives or chronic hives.

Acute hives

Doctors typically recommend second-generation antihistamines as the first-line treatment for acute hives, such as:

  • loratadine (Claritin)
  • desloratadine (Clarinex)
  • fexofenadine (Allegra)
  • cetirizine (Zyrtec)
  • levocetirizine (Xyzal)

They may prescribe a standard dose or increase by up to 4 times if the individual does not respond.

If these medications do not improve symptoms, the doctor may recommend an additional antihistamine, such as cimetidine (Tagamet), famotidine (Pepcid), or ranitidine (Zantac). They may recommend a 3–10-day course of corticosteroids to help control the symptoms in severe cases.

The doctor may prescribe an epinephrine auto-injector if they think the individual is at risk of anaphylaxis, which is a severe allergic reaction that restricts breathing. This provides emergency medicine to treat anaphylaxis quickly.

The doctor will then reassess the individual in 2–6 weeks.

Chronic hives

Doctors may recommend a four-step treatment plan for chronic hives. This approach involves using an antihistamine daily, which may be up to 4 times the regular dosage depending on how the individual responds.

If necessary, they may prescribe a second antihistamine or another medication, such as montelukast (Singulair). With persistent hives, they may suggest a high potency antihistamine, such as hydroxyzine or doxepin.

The final step is for a doctor to refer the individual to a specialist for immunomodulatory therapy. This may involve taking medications such as omalizumab (Xolair) or cyclosporine (Sandimmune).

Once symptoms are under control, a doctor may gradually reduce the dosage of these medications. If the hives have an identifiable cause, such as cold or heat exposure, adopting changes to avoid the triggers wherever possible is also important.

The AAD suggests the following methods for people to reduce irritation and itchiness in hives:

  • applying topical anti-itch medications, such as calamine lotion
  • wearing loose-fitting clothing
  • moisturizing with fragrance-free lotion to prevent dry skin
  • using cold compresses several times per day

However, it is important for individuals to try to determine whether the hives have a specific trigger, in addition to relieving symptoms. If someone has cold hives, for example, a cold compress may make them worse.

Therefore, it is a good idea for people to keep a symptom diary, recording when the hives occur and any factors that might have contributed. Symptom diaries are also useful to refer to at medical appointments. A person can take note of:

  • the date and time the hives appear
  • what they were doing just before they developed
  • what they have had to eat or drink

If any common factors emerge when the hives occur, a person can try to temporarily avoid these to see if it helps. It is important for people to do this with the guidance of a doctor, allergist, or dietitian if someone has food-related hives.

Learn more about remedies and treatments for hives here.

Hives do not last long, taking only 2–3 hours to fade. However, more can appear, which makes the symptoms last longer. Acute hives can develop and resolve on their own within 6 weeks, while chronic hives can last much longer.

Doctors treat acute and chronic hives differently, so it is advisable for people to speak with a medical professional about this symptom, especially if the hives last longer than 6 weeks.

If hives or swelling occur in the mouth and airways, making it difficult to breathe, dial 911 or the number of the nearest emergency department immediately.