The Causes of Allergic Reactions and Allergy Symptoms

The most common allergens are those that act on the respiratory tract, such as pollen or mites. In this article, discover what causes allergies and common allergy symptoms.
The Causes of Allergic Reactions and Allergy Symptoms

Last update: 16 January, 2020

Being allergic to something, whether it be pollen, mites, gluten, or something else, is a very common situation that affects a large part of the population. Today, it’s almost rare to find a person who isn’t allergic to anything. In this regard, it’s estimated that one in four people have some kind of allergy throughout their life. In fact, it’s the most common childhood disease.

An allergy refers to the immune system’s sensitivity to a substance, which causes respiratory, digestive, nervous, or skin changes. In other words, it’s an abnormal immune system reaction to a substance that normally wouldn’t trigger this reaction. Overall, a person can be allergic to any substance.

However, do you know why this happens? In this article, we’ll explain why allergies occur and how they’re diagnosed, as well as common allergy symptoms.

What does it mean to be allergic?

The immune system works continuously, recognizing and eliminating germs from the body to protect it from diseases. However, sometimes, its defense mechanisms are altered.

When this occurs, the system activates very strongly against certain elements that are actually harmless. In other words, it activates many defense mechanisms, such as sneezing, against a substance that doesn’t cause disease. For example, this may be pollen.

Allergy symptoms differ according to the substance you’re allergic to. If you’re allergic to dust mites, you’re most likely to suffer from respiratory allergy symptoms. In other words, you may suffer from coughing, sneezing, and watery eyes, among other things.

A person sneezing, one of the allergy symptoms.

This article may interest you: 4 Home Remedies for All Allergy Types

Common allergy symptoms

As we mentioned above, allergy symptoms depend on the type of allergen. In the same way, they also vary according to the “gateway”. In other words, your symptoms will vary depending on whether you had contact with the substance by eating, touching, or inhaling it.

The most common allergies are related to the respiratory system. Therefore, the most common symptoms are rhinitis and allergic conjunctivitis. Rhinitis causes itchy nose, sneezing, nasal obstruction, and constant runny nose (rhinorrhea). Allergic conjunctivitis is an intense itching of the eyes that is accompanied by constant tearing. Also, people who suffer from it sometimes feel that they have sand in their eyes.

Moreover, it’s important to mention that allergic processes are often associated with asthma. Asthmatics often suffer from coughing, wheezing, and difficulty breathing.

You may like this article: Natural Allergy Relief Remedies

Food allergies

When someone is allergic to a food, the most typical allergy symptoms include tingling in the mouth or itching, which may reach the throat. Also, they may suffer from lip, tongue, or face swelling. Hives may also occur after eating the food. Often, there’s also diarrhea, vomiting, or constant flatulence.

The foods that cause the most allergies are milk, nuts, and eggs.

A person getting allergy tests from a doctor.

Drug allergies

Many people are allergic to certain drugs. In fact, doctors have to ask you if you’re allergic to any substance in a consultation. This type of allergy is often accompanied by skin reactions, such as hives, rashes, and itching.


Anaphylaxis occurs when the allergic reaction is extremely severe. What happens is that the immune system releases substances that suddenly lower blood pressure. Then, the airways narrow and make it harder to breathe.

It can happen very quickly after coming into contact with the substance the person is allergic to. For example, it’s relatively common in those who are allergic to bee stings.

When someone suffers an anaphylactic reaction, their pulse accelerates and becomes weaker. In the same way, a rash usually appears on the skin, as well as nausea or vomiting. In these cases, it’s important to go to the emergency room.


Many people are allergic to different substances. Therefore, it’s important to know the most common allergy symptoms. This way, you can guide your doctor into detecting what causes that reaction so you can avoid the allergen.

It might interest you...
Allergy Tests: Types and Procedures
Step To Health
Read it in Step To Health
Allergy Tests: Types and Procedures

There are several different types of allergy tests. Generally speaking, they are medical tests that include a set of procedures that identify aller...