Sweat allergy (cholinergic urticaria) is a type of hives that occurs with increased body temperature. It typically develops when you exercise or sweat. Most of the time, when cholinergic urticaria occurs, it disappears on its own within a few hours.
In severe cases, cholinergic urticaria may sometimes be associated with exercise-induced anaphylaxis. In this case, seek medical help immediately. If you have an epinephrine injector, administer your medication without waiting for help to arrive.
Cholinergic Urticaria (Sweat Allergy) Symptoms
If you are experiencing cholinergic urticaria, these may be:
- Bumps (small, raised bumps on the skin)
- Redness around the bumps
These bumps typically develop within the first six minutes of exercise. Your symptoms may worsen over the next 12 to 25 minutes.
Although the bumps can appear on your body, they usually start on your chest and neck first. They can then spread to other areas. These bumps can last from a few minutes to about four hours after exercise.
You may experience symptoms that are not related to the surface of your skin. These are:
- Stomach ache
Cholinergic urticaria may also be accompanied by exercise-induced anaphylaxis, a more severe allergic reaction to exercise. Its symptoms can be life-threatening and require immediate medical attention. Call 112 if you experience these:
- Difficulty breathing
- Stomach ache
What causes cholinergic urticaria and who is at risk?
Cholinergic urticaria occurs when your body temperature rises. This can happen for several reasons such as:
- Taking a warm bath or shower
- Being in a warm room
- Eating spicy food
- Being sad or angry
- Have anxiety
Whatever activity or emotion raises your body temperature, it also triggers your body to release histamine. This is what causes the symptoms of cholinergic urticaria to appear.
Anyone can develop cholinergic urticaria, but men are more affected. Cholinergic urticaria usually begins around the age of 16 and may continue until the age of 30. If you experience other types of hives or have another skin condition, you may be more susceptible to cholinergic urticaria.
How is Cholinergic Urticaria diagnosed?
If your symptoms are not severe but are affecting your lifestyle, see your doctor. A simple assessment and conversation about your symptoms may be enough for them to diagnose cholinergic urticaria.
In some cases, your doctor may want to run tests to gather more information about the condition. These may include:
A passive warm-up test: This raises your body temperature with warm water or an increased room temperature. Your doctor can observe your body’s response when exposed to increased heat.
A methacholine skin challenge test: Your doctor will inject methacholine into your body and watch for a reaction.
An exercise challenge test: Your doctor will give you exercise and monitor for signs of cholinergic urticaria. You may also be measured with other medical instruments during the test.
If you suspect you are experiencing exercise-induced anaphylaxis, you should see a doctor immediately and be treated as soon as symptoms appear.
Sweat Allergy Treatment Options
Your doctor will work with you on a treatment plan that suits your individual needs.
If your symptoms are mild, simple lifestyle changes may be all you need. However, if you are an athlete or engage in physical or strenuous activity in your daily life, lifestyle changes can be difficult to adapt. Medication may be a better option for some.