Cholinergic urticaria can develop when you’re hot enough to sweat. For some people reaching a certain temperature may trigger the release of histamine – a chemical your body produces during an allergic reaction.  It can cause inflammation and heat allergy rash symptoms.

Any actions you take that raise your body temperature have the potential to cause a breakout of hives. This includes taking a hot bath or shower.

Other causes of allergic heat rash could include:

• Exercising
• Eating hot or spicy foods
• Emotional stress
• Using a blanket to keep warm
• Wearing warm clothes
• Sitting in a sauna

Usually, it develops after a person has eaten something they’re possibly allergic to an hour before doing physical activity.

Anaphylaxis is a severe systemic allergic reaction. It can come on suddenly and be life-threatening so it should be treated as a medical emergency. You must seek medical help immediately (more about treatment here).

Signs and symptoms of anaphylaxis include:

• Widespread skin reactions, including hives and itching and flushed or pale skin
• Low blood pressure (hypotension)
• Constriction of your airways and a swollen tongue or throat, which may cause wheezing and trouble breathing
• A weak and rapid pulse
• Nausea, vomiting or diarrhea
• Dizziness or fainting

You may first see symptoms on the and neck, which could then spread to the limbs and face. Usually, symptoms clear within 90 minutes, providing you take action to cool down.

A rare complication of heat allergy rash is anaphylaxis. Researchers don’t fully know why some people with heat allergy rash go on to develop anaphylaxis, but they think it’s probably related to exercise-induced anaphylaxis. This happens when anaphylactic symptoms occur after you’ve done physical activity. Food-dependent anaphylaxis can also occur after exercising.

Usually, it develops after a person has eaten something they’re possibly allergic to an hour before doing physical activity.

Anaphylaxis is a severe systemic allergic reaction. It can come on suddenly and be life-threatening so it should be treated as a medical emergency. You must seek medical help immediately (more about treatment here).

Signs and symptoms of anaphylaxis include:

• Widespread skin reactions, including hives and itching and flushed or pale skin
• Low blood pressure (hypotension)
• Constriction of your airways and a swollen tongue or throat, which may cause wheezing and trouble breathing
• A weak and rapid pulse
• Nausea, vomiting or diarrhea
• Dizziness or fainting

You would usually spend 10–15 minutes on the treadmill or bike until you reach the point of sweating.

Passive warming test: If the exercise challenge test suggests you have cholinergic urticaria, you may have a passive warming test as well. This involves raising your body temperature with a warm bath, for example.

Sometimes your healthcare provider may use a methacholine injection to trigger hives. But only a third of people show a positive result so this test can’t be used alone in a cholinergic urticaria diagnosis.

This all depends on the severity of your symptoms. If they’re mild, you may only have to make a few lifestyle changes, such as avoiding spicy foods and intense exercise. Stopping strenuous physical activity if you’re an athlete may be more difficult.

Antihistamines can often relieve allergic heat rash. But more severe symptoms could require different treatments. If you’ve ever developed anaphylaxis from getting too hot, your healthcare provider is likely to prescribe epinephrine auto-injectors. This is more likely with a history of exercise-induced anaphylaxis.

Your doctor will review your existing medications when considering prescribing epinephrine as certain antihypertensive drugs may impact its effectiveness. Carry two auto-injectors at all times. And go to the hospital immediately even if the first dose helped you to feel better in case of a delayed secondary reaction.  

But finding ways to keep the skin cool could help reduce symptoms a little quicker. For mild cases, you could prevent heat rash from developing by wearing loose fitting clothing and staying in the shade. Or, try to work out at cooler times of the day to avoid excessive sweating. This is especially important during hot weather.

Anything that can raise your body temperature enough for you to sweat could cause a flare. Usually, lifestyle changes are enough to prevent flares from happening as frequently. This may mean avoiding spicy foods and hot baths.

Yes, exercise can cause allergic heat rash because it raises your body temperature. In fact, it’s the most common trigger of cholinergic urticaria.

Yes, exercise can cause allergic heat rash because it raises your body temperature. In fact, it’s the most common trigger of cholinergic urticaria.

Heat allergy rash is a type of skin rash and tends to clear up on its own within 90 minutes, if you stop doing what’s making you feel hot. The release of histamine is what causes hives to appear, researchers are still trying to understand exactly how body temperature affects this.

Heat allergy rash is a type of skin rash and tends to clear up on its own within 90 minutes, if you stop doing what’s making you feel hot. The release of histamine is what causes hives to appear, researchers are still trying to understand exactly how body temperature affects this.

Heat allergy rash is a type of skin rash and tends to clear up on its own within 90 minutes, if you stop doing what’s making you feel hot. The release of histamine is what causes hives to appear, researchers are still trying to understand exactly how body temperature affects this.

2. Vermeide die Verbreitung allergener Erdnussproteine

• Mache es dir zur Gewohnheit, am Tisch zu essen und einen Teller zu verwenden.
• Reinige Küchenoberflächen, an denen Erdnussrückstände vorhanden sein könnten, mit einem Einwegtuch.
• Dasselbe gilt für Pfannen und Utensilien, wenn du mit Erdnüssen kochst.

3. Und achte darauf, sie nicht versehentlich zu essen

• Teile weder Tassen noch Besteck, da Erdnussproteine im Speichel zurückbleiben können.
• Warne auch dein Date, dass du niemanden küssen kannst, nachdem er oder sie Erdnüsse gegessen hat.
• Lasse dich von den Hunden anderer Menschen nicht ablecken, es sei denn, du weißt sicher, dass ihre Besitzerin oder ihr Besitzer erdnussfreies Haustierfutter und Leckerlis kauft.

Common causes of allergic heat rash include exercising, taking hot baths and eating hot or spicy foods. Usually, making lifestyle changes, such as not doing vigorous exercise can prevent hives from developing, but this can be more difficult for athletes. In these instances, a healthcare provider may suggest treating symptoms when they appear with antihistamines.

Allergic heat rash is different from prickly heat because it’s not caused by blocked sweat glands and typically goes away after a person cools down. If you’ve noticed your heat hives are taking longer to disappear than usual, or you’re experiencing other symptoms, please do speak with a healthcare provider. Additionally, if you’re struggling to breathe seek urgent medical treatment as this can be a symptom of anaphylaxis.