An allergy (allergies) is an overly sensitive (hypersensitive) disorder of the immune system. If you are allergic, your immune system abnormally responds to your triggers.
These triggers are called allergen or antigen.
Includes pollen, dust mites, mold spores, pet dander, food, insect stings, and medicines.
Allergic conjunctivitis is an eye inflammation caused by an allergic reaction to substances like pollen or mold spores. The inside of your eyelids and the covering of your eyeball have a membrane called the conjunctiva.
Allergic rhinitis, also known as hay fever, is a type of inflammation in the nose which occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, itchy, watery eyes, and swelling around the eyes.
Asthma is a condition in which your airways narrow and swell and may produce extra mucus. This can make breathing difficult and trigger coughing, a whistling sound (wheezing) when you breathe out and shortness of breath.
A chronic cough is when a cough lasts longer than 8 weeks in adults or 4 weeks in children. Common causes include asthma, allergies, gastroesophageal reflux disease (GERD), or bronchitis.
Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease that causes obstructed airflow from the lungs. Symptoms include breathing difficulty, cough, mucus (sputum) production and wheezing.
An immune deficiency disease occurs when the immune system is not working properly. If you are born with a deficiency or if there is a genetic cause, it is called primary immunodeficiency disease.
A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure.
An allergic reaction to insects that don’t sting or bite, like cockroaches or dust mites, is different. You may sneeze, cough, have a runny or stuffy nose, or itchy eyes, nose, mouth or throat.
A drug allergy is the abnormal reaction of your immune system to a medication. Any medication — over-the-counter, prescription or herbal — is capable of inducing a drug allergy.
Eczema is a common skin condition that leads to itchy, cracked, and inflamed skin. Food and environmental allergies can trigger eczema.
Hives, also known as urticaria, are itchy, raised welts that are found on the skin. They are usually red, pink, or flesh-colored can move to occur sporadically. In some cases, hives are caused by an allergic reaction to a medication or food or a reaction to an irritant in the environment.