Peanuts, cats, dust, grass and mosquito bites: all fairly common triggers for allergies. But have you ever heard of someone being allergic to exercise?
Turns out it's not as silly as it sounds. But before you go telling your personal trainer you're allergic to sit ups, it's (unfortunately) not quite that simple.
"It is possible to develop allergic symptoms as a result of exercise," Professor Mimi Tang, group leader of Allergy and Immune Disorders at Murdoch Childrens Research Institute told The Huffington Post Australia.
"You're not actually allergic to the exercise itself, but some allergic reactions can be triggered by exercise. I suppose you could say you were allergic to exercise... it's an interesting way to think about it."
According to Dr Raymond Mullins, an Australian consultant physician practicing in the specialty of clinical immunology and allergy, exercise can actually trigger asthma, rhinitis, urticaria and, at the more extreme end of the scale, anaphylaxis.
Cholinergic urticaria (otherwise known as 'sweating hives' or 'heat bumps') is a common condition affecting many young adults, and is triggered by -- you guessed it -- sweat.
"Sweating hives occur because you sweat when you exercise", Mullins told HuffPost Australia. "Of course you can sweat for other reasons -- you can sweat when you're stressed, or if you bite into a chilli, or consume alcohol or caffeine -- but exercise would be the dominant one."
In terms of symptoms, according to Mullins' article on the subject, they "usually develop during or just after the cessation of exercise and normally resolve within an hour. Occasional patients develop wheezing/tight chest like asthma. Increases in blood histamine levels have been described, consistent with mast cell degranulation being involved in the cause of symptoms."
As for treatment, Mullins said antihistimines taken as a preventative measure can prove effective. So if you know you're going to go for a big run later in the day, chow down on a Claratyne beforehand and you should be right as rain.
"Exercise anaphylaxis is not common, but I probably see about one [case] a month," Mullins told The Huffington Post Australia.
"The clue here is it doesn't usually happen every time you exercise. With sweating hives, for instance, that usually happens every time the person exercises to the same degree.
"With exercise anaphylaxis, most of the time the person will actually be allergic to a certain type of food they have eaten in the past couple of hours [prior to exercise].
"So a patient will typically present saying, 'I had symptoms six months ago and then it happened again last week, but I exercise three times a week, every week'. So there's confusion as to why it happens when it does."
According to both Mullins and Tang, it really seems to come down to a combination of factors, but essentially the onset of exercise anaphylaxis can often be attributed to a person eating a certain type of food (wheat is the most common offender) and exercising within a few hours of each other.
"It can be confusing as this person may be able to eat wheat without exercising and experience no symptoms," Tang said. "And similarly, they can exercise without having consumed wheat and also have no symptoms.
"Where we see [food-induced exercise anaphylaxis] occur is when someone is allergic to a particular type of food and then does exercise within a few hours of taking a dose of that food.
"And reason we think this happens is because exercise must activate certain factors in the body that makes you more susceptible to an allergic reaction to food, if you are already allergic to that food."
- First described by Sheffer and Austen in 1980, exercise-induced anaphylaxis typically affects young adults.
- Manifestations include itch (92 %), hives (83 %), body swelling/angioedema (78 %), wheeze/asthma symptoms(59 %), sweating (43 %), fainting (32 %), stomach upset (30 %) or blocked and runny nose (rare).
- Some patients have milder or unusual symptoms such as isolated exercise-related hives, abdominal pain or cardiovascular collapse. Unlike cholinergic urticaria, however, the itchy hives are usually quite large and are not induced by heat or sweating alone.
- 'Allergy Capital', Raymond Mullins.
While wheat tends to be the most common culprit, there have also been reports of allergenic foods including seafood, nuts, and some types of fruit and vegetables.
So is it just a case of avoiding eating that particular food prior to exercise?
"Some textbooks say, if you have a food and exercise allergy and you don't exercise within four hours of eating the offending food, you should be okay," Mullins said.
"That is not my experience. I don't believe it's practical advice. Exercise doesn't have to be a 10km run. It can be running for a bus, walking the dog, walking around the shopping centre. In my opinion exercise is unpredictable so if you continue to eat that type of food, you are going to get in trouble again."
Those who think they may be prone to exercise-induced anaphylaxis are advised to seek treatment and advice from a healthcare professional.
Exercise induced asthma
"This is not that uncommon. Plenty of people get sports asthma," Mullins said. "This is largely due to the fact that, when you run, you tend to be drying out your airways and breathing faster, which can be a trigger for spasm of the airways.
"There are a number of drugs and medicines you can take to combat this. Plenty of Olympic athletes have exercise-induced asthma so it's not really an excuse."
Can you be allergic to exercise? Well, no, you can't be allergic to the act of exercising in itself. But you can have other conditions or allergies which could be triggered by exercise, which essentially amounts to the same thing.
If you are concerned you may suffer from an allergy, it is advised you see your health professional.
Just don't sneeze in front of your trainer and tell them you're allergic to burpees -- or you can expect to be told to drop and give 'em 20, stat.