Will hives come back after Benadryl
How long can hives last?
Hives can appear and disappear quickly, with each hive only lasting around 23 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
This article looks at how long hives last, factors that influence their duration, and treatment.
Each hive lasts only
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 someones skin to leak fluid, which accumulates and causes the bump.
Some
- 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
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 persons 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
This suggests that the hives may result from someones 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 persons 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 someones 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 individuals 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 persons 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 310-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 26 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 23 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.
Mayo Clinic Q and A: Chronic Hives Come and Go With No Clear Pattern
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Mayo Clinic Q and A: Chronic Hives Come and Go With No Clear Pattern
DEAR MAYO CLINIC: I woke up this morning with itchy, red welts covering my arms and legs. These have shown up every now and then over the past few months, and now they seem worse than usual. What could be causing this? How is it treated?
ANSWER: What you may be experiencing is chronic hives. Hives (urticaria) are raised, red or white itchy welts on your skin. A sudden onset of hives (acute hives) usually has an identifiable cause or trigger such as insect stings or bites, medications, certain foods, allergens, or infections. Acute hives go away within a few weeks and are usually effectively treated with antihistamines.
Chronic hives are different in that they persist for more than six weeks. The hives seem to come and go with no clear pattern fading over the course of a day or two and then reappearing in a different location a few days later.
Anyone can develop chronic hives, but theyre more common in middle-aged women. Chronic hives can go on for months and even years. They can interfere with sleep, work and other activities. Itching can be severe and may be accompanied by painful swelling. Signs and symptoms tend to flare up with heat, exercise or stress.
One of the biggest sources of frustration with chronic hives is wondering whats causing them. The truth is that its hard to know. Up to 90 percent of cases remain unexplained no external factor or contributing disease can be pinpointed as the cause.
People with chronic hives often are anxious that the hives may be a sign of a serious problem. While its possible for chronic hives to be associated with an underlying illness, such as an infection, autoimmune disorder or certain cancers, this is pretty rare.
A sudden onset of hives can be part of a serious allergic reaction (anaphylaxis). Signs and symptoms may also include swelling of your tongue or throat, breathing problems, and vomiting. And while anaphylaxis requires emergency care, chronic hives dont put you at any sudden risk.
To make an accurate diagnosis, your doctor will want to examine your hives. This may mean seeing your doctor when the hives show up. Your doctor also will want to know how often they appear, how long they last, whether you have any painful swelling, and if you have any other signs and symptoms, such as fever, unintentional weight loss, sensitivity to cold or heat, or pain in your abdomen, bones or joints. If your physical exam and medical history suggest there might be an underlying problem causing the hives, your doctor may recommend additional testing, such as blood tests or skin tests.
If the pattern of your symptoms is consistent with chronic hives, your doctor will want to know if youve started any new medications, traveled recently, or had any infections or other illnesses that might be contributing to the hives.
Providing your hives arent complicated by any additional signs and symptoms, and they cant be explained by any recent changes in your life, your doctor may recommend starting treatment with an over-the-counter nondrowsy antihistamine every day. Common examples include loratadine (Claritin, Alavert), fexofenadine (Allegra) or cetirizine (Zyrtec). If this doesnt work for you, be sure to tell your doctor. He or she may increase your dose or try a different kind of antihistamine. Medications such as corticosteroids or histamine (H2) blockers also are possibilities. If antihistamines dont control the hives, your doctor may prescribe treatment with omalizumab (Xolair), an injectable medicine thats usually given once a month. In most cases, an effective treatment can be found.
Evidence suggests that certain factors such as heat, tight clothing and nonsteroidal anti-inflammatory drugs (NSAIDs) can worsen chronic hives. Try to keep cool, avoid hot showers, and wear loose, comfortable clothing. If you take NSAIDs regularly for pain relief, talk to your doctor about switching to a different form of pain reliever, at least while you continue to have hives.
People often wonder if something in their diets might be causing their hives. Theres very little evidence that certain foods or food additives are responsible for chronic hives. But you may want to keep a food journal alongside a record of your symptoms so that you can detect a pattern, if any. Most doctors dont recommend any specific diet or dietary elimination.
Although you may never know the cause of your hives, you can rest assured that chronic hives are often temporary. Investigators followed more than 200 people with chronic hives for up to five years. They found that about half the people with unexplained chronic hives were free of symptoms within a year. In the majority of cases, chronic hives can be successfully controlled with medications and possibly a few lifestyle changes. (adapted from Mayo Clinic Health Letter) Dr. James Li, Allergic Diseases, Rochester, Minn.
