Exercise-induced anaphylaxis and urticaria are allergic conditions that flare up when a person exercises. Both are triggered by an overreaction of the immune system. However, anaphylaxis (a generalized allergic reaction involving two or more body systems) is a much more dangerous condition than urticaria (red, swollen patches of skin) and may require emergency medical treatment.
Anaphylaxis can include urticaria along with other symptoms (such as wheezing), and may progress to anaphylactic shock, a potentially life-threatening condition that requires immediate treatment.
Younger people are at higher risk for experiencing exercise-induced anaphylaxis and urticaria. In addition, women and those with a family history of atopy (genetic tendency toward allergies) are more likely to experience exercise-induced anaphylaxis.
Antihistamines can be prescribed to both treat and prevent cases of exercise-induced urticaria. However, there is no similar preventative medication for exercise-induced anaphylaxis, and a flare up of this rare condition may require an emergency injection of the drug epinephrine to save the patient’s life.
About exercise-induced reactions
Exercise-induced anaphylaxis and urticaria are rare allergic reactions triggered by activity in certain people. Exercise-induced anaphylaxis is a serious, potentially fatal allergic reaction brought on by exercise. The term anaphylaxis is used when two or more body systems are involved in an allergic reaction (for instance, wheezing and skin rash). The condition can progress to anaphylactic shock, which can involve difficulty breathing and a dangerous drop in blood pressure.
In some instances, exercise-induced anaphylaxis occurs after a person has consumed particular allergenic foods (e.g., fish, milk). In individuals who are susceptible to this condition, the exercise lowers a mechanism in the body known as the mast cell degranulation threshold. The result is the release of histamines and other allergy mediators that are responsible for causing an allergic reaction.
Exercise-induced anaphylaxis tends to affect young people (25 is the mean age of onset), women and those with a family history of atopy (genetic tendency toward allergies) more than other groups.
Exercise-induced urticaria can be a form of a condition known as cholinergic urticaria. Cholinergic urticaria occurs when passive or active warming of the body triggers hives – red, swollen patches of skin that occur in groups. The danger of exercise-induced urticaria usually is less acute than that of anaphylaxis. However, in extreme cases, exercise-induced urticaria can actually develop into anaphylaxis. Most often, exercise-induced urticaria tends to affect people in their middle to late 20s.
Though the danger of the two exercise-induced conditions differs dramatically, they are both allergic reactions that share the same pathway. As an antigen comes into contact with the body, the immune system mistakenly perceives it to be a harmful foreign substance. As part of the allergic reaction that follows, chemicals are released into the body, triggering symptoms.
Types and differences
There are two major forms of exercise-induced anaphylaxis:
- Classic exercise-induced anaphylaxis. The more common form, this condition unfolds in several phases as symptoms become progressively more severe.
- Variant-type exercise-induced anaphylaxis. This form is similar to the classic form, but hives are usually smaller.
The term familial exercised-induced anaphylaxis, is used to classify those with a family history of either the condition itself or atopy (genetic tendency toward allergies).
Exercise-induced urticaria is a form of cholinergic urticaria. Cholinergic urticaria occurs when the body’s core temperature increases by 0.9 degrees Fahrenheit to 2.7 degrees Fahrenheit (0.5 degrees Celsius to 1.5 degrees Celsius). It can be brought on by passive warming (such as from a hot shower) or active warming, as with exercise.
Exercise triggers both exercise-induced anaphylaxis and exercise-induced urticaria. However, those with these conditions do not necessarily suffer an attack every time they exercise.
The factors that cause exercise-induced urticaria are not exactly clear. However, it is known that a rise in core body temperature is the major trigger of cholinergic urticaria, including exercise-induced urticaria. Anything that warms the core body temperature by 0.9 degrees to 2.7 degrees Fahrenheit (0.5 degrees to 1.5 degrees Celsius) can trigger the condition. This includes hot showers, anxiety and exercise.
There are several factors that make symptoms of exercise-induced anaphylaxis more likely. Known triggers include:
- Environmental factors during exercise, including:
- Humidity (either very humid or very dry conditions)
- Temperature (either warm or cold conditions)
- Allergen counts (including pollens, molds and dust)
- Drugs taken prior to exercise, including:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen
- Over-the-counter cold remedies
- Physiologic factors, including times of increased emotional responses, such as during menstruation for women.
In addition, eating any food or some specific foods before exercise can cause anaphylaxis or urticaria. Some patients can also develop exercise-induced anaphylaxis from eating after exercising. Problematic foods include:
- Wheat or wheat gliadin
- Chick peas (garbanzo beans)
- Poppy seeds
- Snails (escargot)
Signs and symptoms
Symptoms of exercise-induced anaphylaxis can appear during or immediately after exercise. The types of symptoms vary depending on which of the two major forms of the condition a person experiences: classic or variant-type.
Classic exercise-induced anaphylaxis symptoms unfold in stages, with the stage of most serious symptoms lasting anywhere from 30 minutes to four hours. Symptoms include:
- Severe itching (pruritus)
- Reddening of the skin
- Breathing difficulties
- Giant hives (including angioedema of the face, palms and soles)
- Blood-pressure drop (hypotension)
- Fainting (syncope)
- Nausea and vomiting
- High-pitched noise during breathing (stridor)
- Vascular collapse
- Abdominal cramps
- Swelling of the face, tongue and hands
- Loss of consciousness
Variant-type exercise-induced anaphylaxis shares many of the same symptoms as the classic form, except giant hives typically are not observed. Instead, a person may exhibit small punctate skin lesions similar to those found in exercise-induced urticaria. Variant-type exercise-induced anaphylaxis can be as life-threatening as the classic form.
Symptoms of exercise-induced urticaria tend to be less serious, and include small, conical, solid elevations of the skin known as pruritic papules. These usually appear on the neck, upper trunk and upper arms and legs. However, hives may appear on any part of the body. In severe cases, angioedema may develop. An attack tends to last between 20 and 90 minutes. Other symptoms of this condition include:
- Palpitations (an awareness of a strong, fast, irregular, abnormal or “galloping” heartbeat)
- Abdominal cramps
- Swelling of the face, tongue or hands
- Sweating and flushing
- Shortness of breath
As with exercise-induced anaphylaxis, symptoms of exercise-induced urticaria can appear during or after exercise. Individuals who notice hives while they are exercising should stop the activity. If the hives persist for longer than 5 to 10 minutes, or if they are accompanied by other symptoms, the patient should contact their physician immediately.
Individuals who suspect that they are experiencing exercise-induced anaphylaxis should also stop exercising and seek immediate medical attention.
Diagnosis and treatment
Physicians generally rely on a medical history and description of symptoms when diagnosing exercise-induced anaphylaxis. They do not use exercise testing when diagnosing the disorder because it is considered too risky.
Exercise-induced urticaria typically is diagnosed by passively warming a patient’s extremity with a heating blanket or warm water to raise the body’s core temperature. The physician then looks for symptoms of urticaria.
A methacholine challenge test also can be used to diagnose exercise-induced urticaria. In this procedure, a mixture of saline and the bronchoconstrictor methacholine is injected under the skin, and the patient is monitored for a reaction. However, some with exercise-induced urticaria will not react to methacholine, so the test is not widely used.
Those who have not been diagnosed with exercise-induced anaphylaxis or urticaria, but who experience sudden hives, pruritus and flushing, may receive an injection of an antihistamine.
If symptoms progress to indicate exercise-induced anaphylaxis, a dose of epinephrine, or adrenaline, will be injected into the patient. This drug constricts the blood vessels, prevents fluid leakage, opens the airways and raises blood pressure. It is the only way to immediately relieve the life–threatening symptoms of anaphylaxis.
Once a diagnosis of exercise-induced anaphylaxis has been established, physicians might suggest that patients carry their own epinephrine auto-injection kit (allergy kit) so they can treat themselves in an emergency. This prescription medication is known as an autoinjector, and the medications generally last 18 months.
Those who are found to have exercise-induced urticaria may be prescribed an antihistamine to relieve symptoms. Antihistamines also can be taken as a preventative measure, as they inhibit the ability of histamines to produce future symptoms of an allergic attack. An epinephrine auto-injector kit may be prescribed to some patients with exercise-induced urticaria, as there is a very small risk that exercise-induced urticaria can develop into exercise-induced anaphylaxis.
A physician may also ask the patient to keep a diary of all foods eaten before exercise. When maintained over a few weeks, this data can reveal patterns between certain foods and the appearance of symptoms. Patients can then avoid foods that appear problematic and see if the symptoms stop.
Preventative medications have not been effective in treating exercise-induced anaphylaxis. However, there are a number of steps an individual can take to either cut down the likelihood of experiencing symptoms, or to increase the odds of surviving an attack that does occur. They include:
- Exercise during the cooler parts of the day, such as early morning and evening.
- Stop exercising as soon as symptoms develop.
- Always carry prescribed emergency medications when exercising.
- Find an exercise partner who can respond in case of emergency.
- Wear a medical bracelet detailing personal exercise–induced anaphylactic triggers.
- Know personal triggers, and avoid them. For example, people should not consume foods that have triggered reactions in the past before they exercise. Physicians may also recommend that patients avoid exercise for four to six hours after a meal or snack.
- Seek immediate medical attention at the first sign of symptoms.
While these steps can benefit many patients, some patients will be required to abstain from certain activities or exercise altogether.
Those who have exercise-induced urticaria should consult a physician about the possible use of prescription antihistamines to prevent symptoms of the disorder. Antihistamines inhibit the ability of the body chemical histamine to produce symptoms of an allergic reaction.
Questions for your doctor
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions regarding exercise-induced anaphylaxis and urticaria:
- Do my symptoms suggest exercise-induced anaphylaxis or urticaria?
- What methods will you use to determine the cause of my symptoms?
- Does this condition pose a danger to my overall health?
- Will I have a reaction every time I exercise?
- How can I lower my risk of having an exercise-induced reaction?
- Now that I have been diagnosed, will I have to completely stop exercising?
- What treatments are available to me?
- How likely is it that I will pass this condition on to my children?
- What symptoms would require me to seek immediate medical attention?
- Should I carry an allergy kit with me at all times?