Did you know that about a third of all people worldwide have at least one allergy? Ranging from food and pet allergies to hay fever and allergies to certain drugs, as well as from barely noticeable to potentially fatal, allergies are as varied as the people who have them.
In our guide, we’ll take a look at the most common types of allergies, what their typical symptoms are, as well as treatment options, and more.
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What is an allergy?
An allergy is an unwanted reaction of your body’s immune system to substances that are typically harmless. Allergies are very common, especially in children, and about a third of all people worldwide have an allergic reaction at least once in their lives. New allergies can develop at any age, while allergies in children can, in some cases, also go away as the child grows up. Allergies present in adults, however, will usually become permanent.
Most common allergies
While it’s possible to be allergic to pretty much everything, even water, some allergies are much more common than others. The most common allergies include:
- grass and tree pollen (hay fever)
- dust mites
- pets, more specifically their hair or skin
- food, especially peanuts, tree nuts, fruit, shellfish, fish, eggs, soy, and cow’s milk
- insect bites, stings, or droppings (e. g. from cockroaches)
- certain kinds of medicine, for example, ibuprofen, aspirin, or antibiotics
- latex
- mould
- household chemicals (such as those in detergents, hair dyes) & cosmetics
- sunlight
Types of allergies
There are four main types of allergies that are distinguished by their exact immune response and the time it takes for symptoms to set in.
Type I: Immediate
This is the most severe form of an allergic reaction, which can lead to life-threatening reactions such as difficulty breathing, low blood pressure, and shock (anaphylaxis) within seconds to minutes of being in contact with the allergen (the substance that triggers the allergy).
Type II: Cytotoxic
Symptoms set in minutes to hours after being in contact with the allergen. They can be light to severe.
Type III: Immune-complex mediated
Symptoms appear after several hours and manifest in conditions such as lupus bouts or serum sickness that can damage parts of the body, such as organs – temporarily or permanently.
Type IV: Delayed hypersensitivity
Symptoms set in at least 48 hours after being in contact with the allergen. This type most often affects the skin, lungs, pancreas, or thyroid.
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Allergy symptoms
Depending on which allergy you have and how severe your allergic reactions are, allergy symptoms can vary widely. Some of the most common allergy symptoms, however, include:
- red, itching, watering eyes
- a runny/blocked nose
- sneezing, wheezing, or coughing
- eczema or skin rashes that may itch (hives)
- asthma & difficulty breathing
- swelling and/or tingling
- in severe cases anaphylaxis, a potentially fatal reaction characterized by low blood pressure; a rapid, weak pulse; shortness of breath; nausea and vomiting; and light-headedness or even loss of consciousness
What causes allergies?
Allergies are an overreaction of your immune system. Right now, there is no known reason why some people’s immune systems overreact to substances that are harmless to other people. Researchers, however, agree that genetics may play a factor, and that living in cleaner, more germ-free environments than we used to may be responsible for the continuous increase in allergies worldwide.
How are allergies diagnosed?
Most allergies are discovered when the affected person first comes into contact with the allergen and experiences symptoms. There are, however, several tests to diagnose allergies before they cause severe symptoms.
The most common allergy test is a skin prick test, where the skin of (typically) your arm is pricked with tiny needles dipped in potential allergens. Subsequently, your doctor will examine the area of your arm that’s been pricked and look for any allergic reactions such as light swelling to let you know which allergens to avoid.
If you’ve had severe allergic reactions before or if there are other factors that speak against a skin prick test (such as medications that might interfere with the result), there are also other types of allergy testing, such as blood tests.
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Allergy treatment
The most important thing to do when you have allergies is to avoid triggering them by staying clear of your allergens as much as possible. Whenever this is not possible, however, there are also medications you can take to alleviate your symptoms, especially antihistamines and epinephrine.
Antihistamines
Whenever your body detects something it deems harmful, it releases a hormone called histamine. While this itself is normal and helpful, in the case of allergies, your body releases histamines upon detecting substances that aren’t actually harmful, and an allergic reaction ensues. Antihistamines inhibit the release of these histamines and can therefore avoid or at least lessen the symptoms of your allergies.
Epinephrine
To counter severe allergic reactions, especially anaphylaxis, you may also use an EpiPen – a one-time injection of epinephrine you can carry on you at all times in case of emergency, that will help normalize your blood pressure and relax your muscles to help with breathing and nausea.
Immunotherapy for hay fever
A way to alleviate allergic reactions permanently is to undergo immunotherapy. Here, you’ll be injected with increasing doses of the substance you’re allergic to to help your body get used to the exposure and teach your immune system not to overreact to it. The therapy usually takes several years, but the results are generally good.
Living with allergies
While allergies in children may go away as the child grows up, allergies in adults usually stay for the rest of their lives. What’s more, new allergies can develop at any time, even though the majority will first manifest in a person’s twenties at the latest.
Living with an allergy means you’ll have to train yourself to check ingredient lists, and to avoid your allergy triggers as much as possible. If you tend to have severe allergic reactions, also be sure to carry an EpiPen on you at all times to counter a possible anaphylaxis.
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Allergy FAQs
Are you looking for some quick-fire answers to your most important questions about allergies? Check out our FAQ:
How long does an allergic reaction last?
Depending on the type of allergy you have and its severity, the symptoms may last from a few hours to several weeks.
How to treat an allergic reaction rash?
Creams and moisturizers can help calm the affected area. If it is inflamed, steroid/cortisone lotions can help, too.
What is an allergen?
An allergen is a substance you are allergic to, such as animal skin or hair, pollen, certain chemicals, or specific foods.
How many allergies are there?
In theory, you can be allergic to almost everything, including sunlight, dust, and even water. As concerns common allergies, however, there are only a few dozen.
How to get rid of allergic reaction on the face?
Make sure not to get in contact with any further allergens, and carefully clean your skin. Steroid/cortisone creams can help reduce inflammation and swelling quickly.
Can allergies cause a cough?
Yes, if your allergy causes your airways to cramp or swell, coughing or wheezing may occur.
Can you develop allergies?
Yes, you can develop new allergies at any age, although most will manifest before you reach the age of 30.
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Allergy resources
Allergies can be scary, especially when you didn’t even know you had them. Fortunately, allergy tests you can take before severe symptoms may occur, such as skin prick tests, can give you can idea about what to be careful with, and medications such as antihistamines and epinephrine can help stop or at least alleviate symptoms. We hope our guide could answer all questions you might have had regarding the most common allergies, and we wish you all the best on your own health journey.
Should you be looking for even more info on allergies and how to find out what you’re allergic to, join Carecircle.org and get in touch with fellow patients, scientists, and carers. In our friendly, free community, you can engage with other people’s posts, write your own, and find help, hope, and control, provided by members dealing with the same conditions as you are.
