What Causes Hives?

Hives, also known as urticaria, are raised, itchy skin welts that can appear anywhere on the body. They are often caused by an allergic reaction to something you have eaten, touched, or inhaled. While hives can be a nuisance, they are usually not serious and will go away on their own within a few days.

There are many different things that can cause hives, but some of the most common include:

In the next section, we'll take a closer look at each of these causes and discuss how to prevent and treat hives.

What Causes Hives

Hives, also known as urticaria, are raised, itchy skin welts that can appear anywhere on the body. They are often caused by an allergic reaction to something you have eaten, touched, or inhaled. While hives can be a nuisance, they are usually not serious and will go away on their own within a few days.

• Allergic reactions
• Certain foods
• Insect bites or stings
• Medications
• Viral infections
• Physical factors
• Stress
• Sun exposure

In some cases, hives can be a sign of a more serious medical condition, such as an autoimmune disease or cancer. If you have hives that are severe, persistent, or accompanied by other symptoms, such as fever, shortness of breath, or swelling of the face, lips, or tongue, it is important to see a doctor right away.

Allergic Reactions

Allergic reactions are one of the most common causes of hives. When you come into contact with an allergen, your body produces antibodies called immunoglobulin E (IgE). These antibodies attach to cells in your skin called mast cells. When you are exposed to the allergen again, the mast cells release histamine and other inflammatory mediators, which cause the symptoms of hives, such as itching, swelling, and redness.

There are many different things that can cause allergic reactions, including:

• Foods: Some of the most common food allergens include peanuts, tree nuts, shellfish, milk, eggs, soy, and wheat.
• Insect bites or stings: Insect bites or stings can cause hives in some people.
• Medications: Some medications, such as penicillin and aspirin, can cause hives as a side effect.
• Latex: Some people are allergic to latex, which is a natural rubber found in many products, such as gloves, condoms, and balloons.
• Pollen: Pollen from trees, grasses, and weeds can cause hives in some people.
• Pet dander: Dander from cats, dogs, and other animals can cause hives in some people.
• Dust mites: Dust mites are tiny creatures that live in dust. They can cause hives in some people.

In some cases, hives can be caused by an allergy to something that you have never been exposed to before. This is called an idiopathic allergy. Idiopathic allergies are often difficult to diagnose and treat.

If you think you may be having an allergic reaction, it is important to see a doctor right away. Treatment for allergic reactions depends on the severity of the reaction and the allergen that is causing it.

Certain Foods

Certain foods are a common cause of hives. These foods are typically allergens, which means that they trigger an allergic reaction in some people. When someone who is allergic to a particular food eats that food, their body produces antibodies called immunoglobulin E (IgE). These antibodies attach to cells in the skin called mast cells. When the person eats the food again, the mast cells release histamine and other inflammatory mediators, which cause the symptoms of hives, such as itching, swelling, and redness.

• Peanuts: Peanuts are one of the most common food allergens. They can cause hives in both children and adults.

Details: Peanuts are a type of legume, and they are related to other legumes, such as beans and lentils. Peanuts are often found in foods such as peanut butter, peanut oil, and candy bars. They can also be hidden in other foods, such as cookies, cakes, and ice cream.

Details: Tree nuts are a type of seed, and they are not related to peanuts. Tree nuts are often found in foods such as trail mix, granola, and nut butters. They can also be hidden in other foods, such as baked goods and ice cream.

Details: Shellfish are a type of seafood, and they are related to other seafood, such as fish and squid. Shellfish are often found in foods such as sushi, seafood stew, and seafood pasta. They can also be hidden in other foods, such as sauces and dips.

Details: Milk is a type of dairy product, and it is produced by cows, goats, and other animals. Milk is often found in foods such as milk, cheese, yogurt, and ice cream. It can also be hidden in other foods, such as baked goods and processed foods.

If you think you may be allergic to a particular food, it is important to see a doctor right away. Treatment for food allergies typically involves avoiding the food that is causing the allergy.

Insect Bites or Stings

Insect bites or stings can cause hives in some people. This is because the venom from the insect can trigger an allergic reaction. When someone who is allergic to insect venom is bitten or stung, their body produces antibodies called immunoglobulin E (IgE). These antibodies attach to cells in the skin called mast cells. When the person is bitten or stung again, the mast cells release histamine and other inflammatory mediators, which cause the symptoms of hives, such as itching, swelling, and redness.

The most common insects that can cause hives are:

• Bees
• Wasps
• Yellow jackets
• Hornets
• Fire ants
• Mosquitoes
• Fleas
• Bed bugs

Hives from insect bites or stings typically appear within a few minutes of being bitten or stung. They can last for a few hours or up to a few days. In some cases, hives from insect bites or stings can be severe and require medical attention.

If you are allergic to insect venom, it is important to take steps to avoid being bitten or stung. These steps include:

• Wearing long sleeves and pants when you are outdoors.
• Using insect repellent.
• Avoiding areas where insects are known to be present.
• Carrying an epinephrine auto-injector (EpiPen) if you have a history of severe allergic reactions to insect bites or stings.

If you are bitten or stung by an insect and develop hives, it is important to see a doctor right away. Treatment for hives from insect bites or stings typically involves taking antihistamines or corticosteroids.

Medications

Some medications can cause hives as a side effect. This is because some medications can trigger an allergic reaction. When someone takes a medication that they are allergic to, their body produces antibodies called immunoglobulin E (IgE). These antibodies attach to cells in the skin called mast cells. When the person takes the medication again, the mast cells release histamine and other inflammatory mediators, which cause the symptoms of hives, such as itching, swelling, and redness.

• Penicillin: Penicillin is a type of antibiotic that is used to treat bacterial infections. It is one of the most common medications that can cause hives.

Details: Penicillin is a beta-lactam antibiotic, which means that it is related to other antibiotics, such as amoxicillin and cephalexin. Penicillin can cause hives in both children and adults. It is important to note that not everyone who takes penicillin will develop hives. Some people are more likely to develop hives from penicillin if they have a history of allergies or if they are taking other medications that can cause hives.

Details: Aspirin can cause hives in both children and adults. It is important to note that not everyone who takes aspirin will develop hives. Some people are more likely to develop hives from aspirin if they have a history of allergies or if they are taking other medications that can cause hives.

Details: Ibuprofen can cause hives in both children and adults. It is important to note that not everyone who takes ibuprofen will develop hives. Some people are more likely to develop hives from ibuprofen if they have a history of allergies or if they are taking other medications that can cause hives.

Details: Acetaminophen can cause hives in both children and adults. It is important to note that not everyone who takes acetaminophen will develop hives. Some people are more likely to develop hives from acetaminophen if they have a history of allergies or if they are taking other medications that can cause hives.

If you think you are having hives from a medication, it is important to see a doctor right away. Treatment for hives from medications typically involves stopping the medication and taking antihistamines or corticosteroids.

Viral Infections

Viral infections can also cause hives. This is because some viruses can trigger an allergic reaction. When someone is infected with a virus that they are allergic to, their body produces antibodies called immunoglobulin E (IgE). These antibodies attach to cells in the skin called mast cells. When the person is infected with the virus again, the mast cells release histamine and other inflammatory mediators, which cause the symptoms of hives, such as itching, swelling, and redness.

The most common viral infections that can cause hives are:

• Epstein-Barr virus (EBV): EBV is a type of herpes virus that is spread through contact with saliva. It can cause a variety of illnesses, including infectious mononucleosis (mono).
• Hepatitis A virus (HAV): HAV is a type of liver infection that is spread through contact with contaminated food or water.
• Hepatitis B virus (HBV): HBV is a type of liver infection that is spread through contact with infected blood or bodily fluids.
• Herpes simplex virus (HSV): HSV is a type of herpes virus that can cause cold sores and genital herpes.
• Influenza virus: Influenza virus is the virus that causes the flu.
• Measles virus: Measles virus is a type of virus that can cause measles.
• Mumps virus: Mumps virus is a type of virus that can cause mumps.
• Rubella virus: Rubella virus is a type of virus that can cause rubella (German measles).
• Varicella-zoster virus (VZV): VZV is a type of herpes virus that can cause chickenpox and shingles.

Hives from viral infections typically appear within a few days of the onset of the infection. They can last for a few days or up to a few weeks. In some cases, hives from viral infections can be severe and require medical attention.

There is no specific treatment for hives caused by viral infections. Treatment typically involves taking antihistamines or corticosteroids to relieve the symptoms. In some cases, antiviral medications may be used to treat the underlying viral infection.

Physical Factors

Physical factors can also cause hives. These factors can irritate the skin and trigger the release of histamine and other inflammatory mediators from mast cells. This can lead to the development of hives.

• Heat: Heat can cause hives in some people. This is because heat can irritate the skin and trigger the release of histamine and other inflammatory mediators from mast cells.

Details: Heat-induced hives can occur in response to hot weather, hot baths or showers, or even exercise. Some people are more likely to develop heat-induced hives if they have a history of allergies or if they are taking certain medications that can cause hives.

Details: Cold-induced hives can occur in response to cold weather, cold water, or even air conditioning. Some people are more likely to develop cold-induced hives if they have a history of allergies or if they are taking certain medications that can cause hives.

Details: Pressure-induced hives can occur in response to tight clothing, backpacks, or even sitting or lying down for too long. Some people are more likely to develop pressure-induced hives if they have a history of allergies or if they are taking certain medications that can cause hives.

Details: Friction-induced hives can occur in response to rubbing or scratching the skin. Some people are more likely to develop friction-induced hives if they have a history of allergies or if they are taking certain medications that can cause hives.

If you think you are having hives from a physical factor, it is important to see a doctor right away. Treatment for hives from physical factors typically involves avoiding the trigger and taking antihistamines or corticosteroids to relieve the symptoms.

Stress

Stress can also cause hives in some people. This is because stress can trigger the release of hormones such as adrenaline and cortisol, which can lead to the release of histamine and other inflammatory mediators from mast cells. This can lead to the development of hives.

• Acute stress: Acute stress is a short-term stressor, such as a job interview or a car accident. Acute stress can cause hives in some people.

Details: Acute stress-induced hives typically appear within minutes or hours of the stressful event. They can last for a few hours or up to a few days.

Details: Chronic stress-induced hives can develop over time. They may come and go, or they may be persistent. Chronic stress-induced hives can be more difficult to treat than acute stress-induced hives.

Details: PTSD-induced hives can be triggered by reminders of the traumatic event. They can also be triggered by stress in general.

Details: Anxiety-induced hives can be triggered by stressful situations or by thinking about stressful things. They can also be triggered by physical symptoms of anxiety, such as a racing heart or shortness of breath.

If you think you are having hives from stress, it is important to see a doctor right away. Treatment for hives from stress typically involves managing the stress and taking antihistamines or corticosteroids to relieve the symptoms.

Sun Exposure

Sun exposure can also cause hives in some people. This is because the ultraviolet (UV) rays in sunlight can damage the skin and trigger the release of histamine and other inflammatory mediators from mast cells. This can lead to the development of hives.

There are two types of sun-induced hives:

• Solar urticaria: Solar urticaria is a rare condition in which hives develop within minutes of sun exposure. The hives typically appear on the areas of the skin that are exposed to the sun, such as the face, neck, arms, and legs. Solar urticaria can be triggered by both UVA and UVB rays.
• Photodermatitis: Photodermatitis is a more common condition in which hives develop after sun exposure, but it may take hours or even days for the hives to appear. Photodermatitis is typically caused by an allergic reaction to a chemical in sunscreen or other skincare products that is activated by sunlight. Photodermatitis can also be caused by certain medications that can make the skin more sensitive to sunlight.

Hives from sun exposure typically last for a few hours or up to a few days. In some cases, hives from sun exposure can be severe and require medical attention.

If you think you are having hives from sun exposure, it is important to see a doctor right away. Treatment for hives from sun exposure typically involves avoiding the sun and taking antihistamines or corticosteroids to relieve the symptoms.

There are a number of things you can do to protect yourself from hives caused by sun exposure:

• Wear protective clothing, such as long sleeves and pants, when you are outdoors.
• Apply sunscreen to all exposed skin before going outdoors. Be sure to choose a sunscreen that is broad-spectrum and has an SPF of 30 or higher.
• Reapply sunscreen every two hours, or more often if you are swimming or sweating.
• Avoid being outdoors during the peak hours of sunlight, which are between 10am and 4pm.
• If you have a history of hives from sun exposure, talk to your doctor about taking a medication to prevent hives before you go outdoors.

FAQ

Here are some frequently asked questions about hives:

Question 1: What are hives?
Answer: Hives, also known as urticaria, are raised, itchy skin welts that can appear anywhere on the body. They are often caused by an allergic reaction to something you have eaten, touched, or inhaled.

Question 2: What are the most common causes of hives?
Answer: The most common causes of hives include food allergies, insect bites or stings, medications, viral infections, physical factors (such as heat, cold, pressure, and friction), stress, and sun exposure.

Question 3: How long do hives typically last?
Answer: Hives typically last for a few hours or up to a few days. In some cases, hives can be chronic and last for months or even years.

Question 4: How can I treat hives?
Answer: Treatment for hives depends on the cause of the hives. In most cases, hives can be treated with over-the-counter antihistamines or corticosteroids. In some cases, prescription medications may be necessary.

Question 5: How can I prevent hives?
Answer: The best way to prevent hives is to avoid the things that trigger them. If you have a food allergy, avoid eating the foods that you are allergic to. If you are allergic to insect bites or stings, take steps to avoid being bitten or stung. If you have hives from physical factors, such as heat or cold, try to avoid those triggers.

Question 6: When should I see a doctor about hives?
Answer: You should see a doctor about hives if they are severe, persistent, or accompanied by other symptoms, such as fever, shortness of breath, or swelling of the face, lips, or tongue.

Question 7: Are hives contagious?
Answer: No, hives are not contagious.

Question 8: What are some tips for managing hives?
Answer: Some tips for managing hives include taking cool baths or showers, applying calamine lotion to the affected areas, and wearing loose, comfortable clothing.

If you have hives, it is important to see a doctor to determine the cause of the hives and to get the appropriate treatment.

In the next section, we'll provide some additional tips for preventing and treating hives.

Tips

Here are some tips for preventing and treating hives:

Tip 1: Identify and avoid triggers

The best way to prevent hives is to avoid the things that trigger them. If you have a food allergy, avoid eating the foods that you are allergic to. If you are allergic to insect bites or stings, take steps to avoid being bitten or stung. If you have hives from physical factors, such as heat or cold, try to avoid those triggers.

Tip 2: Take antihistamines

Antihistamines can help to block the release of histamine, which is the chemical that causes hives. Over-the-counter antihistamines, such as diphenhydramine (Benadryl) and loratadine (Claritin), can be effective in treating hives. In some cases, prescription antihistamines may be necessary.

Tip 3: Apply calamine lotion

Calamine lotion can help to soothe the itching and irritation of hives. Apply calamine lotion to the affected areas several times a day.

Tip 4: Take cool baths or showers

Cool baths or showers can help to reduce the swelling and itching of hives. Take cool baths or showers several times a day, or as needed.

If you have hives, it is important to see a doctor to determine the cause of the hives and to get the appropriate treatment. These tips can help to relieve the symptoms of hives and prevent future outbreaks.

In the next section, we'll provide a summary of the key points discussed in this article.

Conclusion

Hives are a common skin condition that can be caused by a variety of factors, including allergies, infections, physical factors, and stress. Hives can be a nuisance, but they are usually not serious and will go away on their own within a few days.

The main points of this article are:

• Hives are raised, itchy skin welts that can appear anywhere on the body.
• Hives are often caused by an allergic reaction to something you have eaten, touched, or inhaled.
• Other causes of hives include insect bites or stings, medications, viral infections, physical factors (such as heat, cold, pressure, and friction), stress, and sun exposure.
• Hives typically last for a few hours or up to a few days.
• Treatment for hives depends on the cause of the hives and may include antihistamines, corticosteroids, or other medications.
• You can help to prevent hives by avoiding the things that trigger them.

If you have hives, it is important to see a doctor to determine the cause of the hives and to get the appropriate treatment.

Hives can be a nuisance, but they are usually not serious. By following the tips in this article, you can help to prevent and treat hives.