Can dogs get hives from heat
Hives and Rashes (Urticaria) in Dogs
Hives or skin rashes (urticaria) are localized patches of red, swollen, usually itchy, skin. They often develop and disappear suddenly. Hives are relatively uncommon in dogs. The most frequent causes are insect bites or stings, shampoos, and medications. Other causes include contact with toxic plants or chemicals. Friction, sunlight, heat, exercise, stress, and genetic abnormalities may cause or intensify the rash. Hives may develop after inhaling or consuming allergens. Hives can be seen while a dog is in estrus ("in heat") or seen in puppies with intestinal parasites ("worms").
The wheals (eruptions) appear within a few minutes or hours of exposure to the causative agent. In severe cases, the skin eruptions are preceded by fever, poor appetite, or dullness. They can develop on any part of the body but occur mainly on the back, flanks, neck, eyelids, and legs. In advanced cases, they may be found on the mucous membranes of the mouth, nose, lining of the eyes, rectum, and vagina.
Often, hives disappear as rapidly as they arise, usually within a few hours. Treatment may not be required. They may return rapidly if exposure to the cause is not eliminated, however. Also, if your dog develops hives after receiving a vaccination or medication, contact your veterinarian immediately to see if treatment is needed. Treatment may include rapid-acting corticosteroids. If hives are chronic, environmental or food allergens should be considered as potential causes. Death does not commonly occur, unless anaphylaxis (a severe allergic event) or swelling of the respiratory tract is present.
Also see professional content regarding urticaria.
Dog Hives (Urticaria | welts): Causes, Diagnosis & Treatment
What Are Dog Hives (Urticaria)?
Hives, otherwise known as urticaria by medical professionals, are one abnormality you may see. They occur when your dog is allergic to something, such as an insect, medication, or food. Recognizing hives in dogs and understanding the cause is essential to relieving your dogs discomfort and preventing dog hives in the future.
What do dog hives look like?
- Dog hives look like raised bumps on the skin, usually about the size of a nickel.
- Hives are usually red in color; however, you may not notice redness if they are on a very furry part of your dog. In this case, your pets hives may only look like fur-covered bumps. Sometimes, its difficult to see the raised bumps, and you may only feel them when petting your dog.
- Dog hives can appear anywhere on the body, including the face, tongue, neck, legs, chest, abdomen, or back. They can affect just one area of the body or the entire body.
- Dog hives are very itchy. This may be the first thing you notice before seeing or feeling hives on your dogs skin. Your dog will likely be trying to scratch, lick, or bite the areas affected as it will be itchy.
- Hives usually happen very fast within minutes after exposure to whatever caused them.
- You may notice excessive drooling and a swollen/puffy face if the hives affect your dogs throat or mouth.
What causes hives on a dog?
Dog hives are almost always related to exposure to an allergen. Once exposed to an allergen, mast cells in your dogs body release a substance called histamine. Histamine causes blood vessels to dilate, which leads to raised welts on your dogs skin.
The most common allergens causing dog hives include:
- Insect bite or sting, or ingesting an insect (photo recommendation: dog playing with bee)
- Vaccinations
- Acute allergic reactions to medications (chemotherapy, vitamin K, antibiotics)
- Food allergies
- Environmental allergies (grasses, trees, mold, dust mites, etc.)
- Contact allergens such as shampoos, insecticides, cleaning products
- Ingesting or skin exposure to toxic plants
Much less common causes of hives in dogs include prolonged exposure to extreme temperatures (hot or cold), strenuous exercise, parasites, or significant psychological stress.
Insect bites/stings, food, and medications are the most common causes of hives in dogs.
How are dog hives diagnosed?
As a pet parent, it can be worrisome to see these skin rashes, but luckily, for your vet to diagnose your dogs hives. Your vet will use a combination of your history and their physical examination findings.
Its essential to think about anything new your dog may have been exposed to. Did you see them playing with a bee? Were they recently vaccinated? Did they start a new medication or a new food? During the physical exam, your veterinarian will look at your dogs skin to evaluate hives and where the hives are located.
If your veterinarian is having trouble diagnosing your dogs hives or the reason for their hives, they may perform additional diagnostics, such as blood work, skin cytology, skin scrapings, or fecal analysis.
How to treat & get rid of dog hives?
Treatment for hives in dogs can be simple or more extensive, depending on the cause, severity, and duration of the allergic reaction.
To get your dog quick relief from the swelling and itchiness related to hives, your veterinarian will usually administer an injection of diphenhydramine (an antihistamine) and a corticosteroid. Once your dog is feeling better and discharged from the hospital, your veterinarian may also recommend that you continue giving your dog Benadryl two to three times a day at home for a couple of days.
To prevent hives from reoccurring, you need to understand what caused them in the first place so that you can avoid the allergen in the future. If there is no apparent cause for your dogs hives (such as insect bite, medication, or vaccinations), it may be more challenging to understand how to prevent hives in the future. Environmental and dietary allergies are two possible causes of hives that may require further diagnostics and treatment.
Environmental allergies
If your dog has recurrent hives or has other signs of allergies, your veterinarian may recommend testing for environmental allergies with serum allergy testing or intradermal allergy testing. With these results, your veterinarian can create a plan to desensitize your dog to these allergies with allergen-specific immunotherapy.
If you determine that you cannot eliminate the allergens in your dogs environment or pursue allergen-specific immunotherapy treatment, your veterinarian may recommend:
- Giving your dog daily antihistamines (such as Benadryl, zyrtec, or hydroxyzine)
- Giving your dog other prescription-strength allergy medications such as apoquel or cytopoint
- Starting daily skin health supplements, such as omega-three fatty acids.
- Frequently bathing your dog with medicated high-quality shampoo
Food allergies
Allergies that stem from food can also cause recurrent episodes of hives in dogs. The most common cause of allergies in dogs include chicken, beef, dairy, and egg 2. Recurrent episodes of hives can also be related to dietary allergies. To diagnose a food allergy, your veterinarian may recommend a diet trial for 6-8 weeks with a prescription food or an over-the-counter diet with a different protein source, like fish or venison. If your dog responds positively to a food trial, you can continue the special diet long term.
Are dog hives dangerous?
Dog hives are rarely life-threatening. However, there are a few less common situations where hives can affect your dogs breathing and become dangerous.
- Hives in the face, neck, or throat can cause severe swelling that impacts breathing, which can become life-threatening.
- The presence of hives anywhere may indicate your dog is having or about to have an anaphylactic reaction, which causes constriction of airways and difficulty breathing. 3 Besides hives, other signs of anaphylaxis include vomiting, diarrhea, facial swelling, drooling, blue gum color, and collapse.
If you notice that your dog has hives, pay particular attention to how they are breathing and for any other concerning changes in their behavior. If you are concerned your dog may be having severe allergic reactions, take them to the emergency room immediately to rule out a medical emergency.
At-home remedies for dog hives
If possible, take your dog to the veterinarian if you notice they have hives, especially if this is a first-time problem. If your dog chronically or intermittently has hives and the issue has previously been discussed with a veterinarian, some at-home remedies may help relieve the allergic reaction.
- If the hives are not affecting your dogs face, neck, throat, or ability to swallow, you can administer Benadryl by mouth. Always discuss if this is appropriate for your dog with your veterinarian first and receive instructions about dosage and frequency.
- If the hives were caused by a contact allergen (such as grasses/trees or chemicals) or insect bites you can help relieve itchiness by bathing with a gentle oatmeal-based dog shampoo can help your dog feel more comfortable.
- Apply a cold compress to the hives or the most severely affected areas of your dogs skin. Be careful never to apply a cold compress for more than 10 minutes at one time, and always wrap the ice or cold object in a towel before applying it to your dogs skin.
Cholinergic Urticaria: Can Heat Cause Hives?
Hives are a skin reaction of itchy bumps that may burn or sting. They can develop not only from an immune response to an allergen but also to heat.
While you may think of hives or urticaria as resulting from an allergic reaction, they can also be caused by heat. These are called heat hives or cholinergic urticaria.
In some people, a rise in temperature can produce the chemical histamine, similar to what happens when your immune system fights allergies. Histamine dilates blood vessels and results in swelling.
There is limited research on cholinergic urticaria. The few available studies estimate a wide prevalence range of
If you notice hives tend to break out when your body temperature rises, it may be a sign that heat triggers your hives. Any exposure to heat could potentially trigger heat hives. This can include:
- bathing in warm or hot water
- being near a heat source like a stove
- being outdoors in the sun
- eating hot food
According to research from 2022, physical factors that can contribute to the development of heat hives include:
- being allergic to sweat
- clogged sweat ducts, lack of sweating
- medications or substances that affect the neurotransmitter acetylcholine
Although being allergic to sweat is rare, research shows that 66% of patients who get heat hives also have a histamine response against antigens in their sweat.
In rare cases, heat hives
Get step-by-step instructions on how to use an EpiPen.
Heat rash vs. hives
Heat hives share similar causes and symptoms with many forms of heat rash, also known as miliaria.
Heat rash can also be
While heat rash tends to fade on its own, consider visiting your doctor for more severe or persistent cases. Your doctor can provide a proper diagnosis and help you determine whether youre experiencing hives or heat rash.
The symptoms of heat hives are similar to hives caused by other triggers such as insect bites, allergies, or medications.
Hives can appear as red, itchy welts ranging in size from less than half an inch up to several inches in diameter. Hives on darker skin tones may appear closer to the color of the skin.
Most cases of hives caused by heat appear within a few minutes after exposure and will subside within 1-2 hours. However, heat hives can also be accompanied by angioedema, which is swelling beneath the affected skin caused by leaking blood vessels.
In some cases, you can also experience other symptoms along with heat hives. These include:
- fatigue or weakness.
- faintness
- nausea
- diarrhea
- headache
You may be experiencing exercise-induced anaphylaxis if you also have the following symptoms:
- difficulty breathing
- wheezing
- abdominal pain
- nausea
- headache
Call 911 if you experience these symptoms. If you have an EpiPen, you should administer the medication while you wait for help to arrive.
If your symptoms arent severe but interfere with your lifestyle, see your doctor. A simple evaluation and conversation about your symptoms may be enough for them to diagnose heat hives.
Sometimes, your doctor may want to conduct tests to gather more information about the condition. These may include:
- A passive warming test: This will raise your body temperature with warm water or an increased room temperature. Your doctor can observe your bodys reaction when exposed to increased heat.
- A methacholine skin challenge test: Your doctor may inject a medication called methacholine into your body and observe for a reaction. However, not everyone with heat hives gets a positive result, so the doctor may use this test in combination with others.
- An exercise challenge test: Your doctor will have you exercise and watch for symptoms of CU. You may also be measured with other medical instruments during the test.
You should see a doctor immediately if you suspect you have exercise-induced anaphylaxis, which must be attended to as soon as symptoms occur.
Many cases of heat hives fade on their own in a few hours, but certain home remedies, prescription medications, and prevention techniques can ease symptoms and alleviate flare-ups.
Natural remedies
Home remedies you can try include aloe vera, which has known anti-itching properties, or a colloidal oatmeal bath, which
But prior to topical applications of this sort, remember to check the ingredients to ensure that you arent allergic to any of them.
You can also take a few precautions to help prevent heat hives:
- Try to keep cool while exercising.
- Prevent exposure to areas of high humidity.
- Avoid prolonged periods of direct sunlight exposure.
Medications
If such home remedies dont work, your doctor may recommend beginning taking an antihistamine such as:
- H1 antihistamines such as citirizine (Zyrtec, Aller-Tec, and Alleroff) or loratadine (Claritin)
- H2 antihistamines (H2 blockers or antagonists) such as famotidine (Pepcid, Pepcid AC) or cimetidine (Tagamet, Tagamet HB)
If these medications dont relieve the symptoms sufficiently, your doctor
In some cases, your doctor may prescribe a medication off-label. One example of such medication is dupilumab (Dupixent), which is another biologic medication that
Most instances of heat hives can be treated at home and eventually fade on their own. However, you should seek immediate medical attention if swelling occurs in your throat that makes it difficult to breathe. This can be a sign of a serious allergic reaction and anaphylaxis.
You and your doctor can work to identify the specific triggers of your heat hives and develop a prevention plan with ways to ease symptoms if flare-ups do occur.
