Atopy is a specific category of allergy. It isn’t a single disorder but rather a way to describe a group of disorders. Atopic conditions are often the result of your immune system overreacting to some trigger.

Experts believe that between 10 and 30 percent of people in higher income countries are affected by atopy.

Different atopic conditions can have different symptoms, and triggers can vary from person to person, but they all share some of the same underlying immune mechanisms. They are part of a group of conditions known as type I hypersensitivity disorders.

Atopic conditions aren’t uncommon. Some of the most frequently diagnosed atopic conditions include:

Let’s take a closer look at how atopy works and how these various conditions are linked.

To understand atopy, we need to talk about antigens and antibodies.

Antigens are foreign substances that can trigger an immune response. They can include all sorts of substances, from mold spores to latex, metals, pollen, and pet dander.

Antibodies, also called immunoglobulins, are the molecules your immune system makes in response to antigens. Your body can tell different antigens apart and may create antibodies tailored to each one. This is why your atopic condition might be triggered by one antigen but not another.

During atopy, your body responds to an otherwise harmless or mild antigen by making too much of a specific antibody called immunoglobulin E (IgE). This leads to the release of histamine and other chemicals that cause inflammation.

Symptoms of atopic conditions often affect your eyes, nose, lungs, and skin. For type I hypersensitivity disorders, including atopy, you can usually expect an immune response within 1 hour after being exposed to a trigger.

The exact causes of atopy are unknown, but evidence strongly points toward genetics.

Research has looked at atopy in twins, in families, and in animals. The genes that increase your risk of making too much IgE are inherited. Experts believe that multiple genes work in concert to create these conditions as opposed to a single gene.

Atopy is also triggered by external substances, so environmental factors play a role, too.

The hygiene hypothesis proposes that atopic conditions are caused by a lack of exposure to antigens in early childhood. It seeks to explain why increased rates of atopic conditions mirror the increase of hygiene standards over the last 100 years. However, this idea still hasn’t been verified and needs to be studied more.

There are many atopic conditions. Here we’ll cover some of the most common. Know that there are many others.

Asthma

Asthma is a condition that affects your lungs. It’s very common, especially in children. Symptoms can include:

Allergic asthma is a specific type of asthma. It’s an atopic condition, meaning your symptoms are caused by your body producing too much IgE in response to a trigger. Allergic asthma accounts for about 60 percent of all asthma cases, according to the Asthma and Allergy Foundation of America.

Allergic rhinitis

Allergenic rhinitis, sometimes called hay fever, is an atopic condition that mostly affects your nose and sinuses. Common symptoms include:

Allergenic rhinitis can be chronic or seasonal. It affects as many as 1 in 6 people.

Eczema

Atopic dermatitis is a form of eczema. It’s an atopic condition with symptoms that affect your skin, such as:

Atopic dermatitis is very common, affecting from 2 to 10 percent of adults and 10 to 30 percent of children.

Allergic conjunctivitis

Allergic conjunctivitis is an atopic condition affecting your eyes. It’s often seasonal and usually consists of:

Experts believe allergic conjunctivitis affects 10 to 30 percent of people, but most don’t seek treatment for the symptoms.

Atopic triggers can be different from person to person. You might have one trigger, or you might have several.

Some common triggers can be found in:

One of the most important parts of treating atopy is knowing what your triggers are and avoiding them as much as possible.

Atopy is a type of allergy that involves IgE production. But there are many types of potential allergies, and they can involve other mechanisms besides IgE.

So all atopic conditions are allergic conditions, but not all allergic conditions are atopic.

Allergies, as a whole, are the most common type of disorder in humans.

Atopic conditions are sometimes treatable using home remedies or over-the-counter drugs. If your symptoms are mild and you’re able to manage them on your own, you might not need to see a doctor.

But if you have an atopic condition that impacts your ability to enjoy your typical routines, you might want to discuss it with a physician or a specialist, such as an allergist.

In the case of asthma, you should set up an appointment with a doctor. Anything that impacts your ability to breathe is potentially serious and deserves a medical evaluation.

Atopy is a specific type of allergy. If you have an atopic condition, your immune system usually overreacts to certain triggers and produces too much IgE, causing inflammation. Depending on your condition, the symptoms of inflammation can be anything from a rash to watery eyes, a runny nose, or a restricted airway.

Atopic conditions aren’t uncommon, and many times you can treat them by avoiding your triggers and using over-the-counter drugs or home remedies.

If you think you might have an atopic condition, a physician or allergist can make a diagnosis and help create a treatment plan that fits your needs.