A person shows strong unusual hypersensitive reactions when exposed to certain substances present in the air.

Identify the condition.

Name the cells responsible for such reactions.

What precaution should be taken to avoid such reactions?

Identification

The hypersensitivity of a person to some foreign substance coming in contact with or entering the body is termed as allergy.

Description

Allergy is the exaggerated response of the immune system to certain antigens present in the environment. The substances against which such immune response is produced are called allergens. Common allergens include:

• Mites
• Dust
• Pollens etc.

Besides, the sensitivities to allergens vary from person to person.

Final answer
Allergy


Cells in allergic reactions

Mast cells take part in allergic reactions by releasing histamine and serotonin.

Mechanism

When allergens enter the body, they crosslink the immunoglobulins (IgE) on the surface of the mast cells. This results in the release of histamine and other chemicals from the mast cells and results in allergic reactions.


Final answer
Mast cells


Precautions

Precautions to avoid allergic reactions mainly involve the identification of the allergen and then suitable methods to prevent and treat the allergy.

Identification of the allergen

• The identification of the allergen can be done with a skin prick test where various allergens are introduced into skin in the form of droplets.
• A positive (histamine) and negative control (saline) is also introduced.
• After an hour, the patient's skin is checked for any allergic reactions.
• A reaction similar to the positive control confirms that the patient is allergic to that allergen.

Medication

Taking the prescribed medicines like adrenalin, antihistamines and steroids help in preventing severe allergic reactions as these drugs work against histamines, reducing its effect.