Allergies are hypersensitive responses from the immune system to substances that either enter or come into contact with the body.

These substances commonly include materials such as pet dander, pollen, or bee venom. Anything can be an allergen if the immune system has an adverse reaction.

A substance that causes an allergic reaction is called an allergen. Allergens can be found in food, drinks, or the environment.

Many allergens are harmless and do not affect most people.

If a person is allergic to a substance, such as pollen, their immune system reacts to the substance as if it was foreign and harmful, and tries to destroy it.

Research indicates that 30 percent of adults and 40 percent of children in the United States (U.S.) have allergies.

Fast facts on allergies

• Allergies are the result of an inappropriate immune response to a normally harmless substance.
• Some of the most common allergens are dust, pollen, and nuts. They can cause sneezing, peeling skin, and vomiting.
•  Anaphylaxis is a serious allergic reaction that can be life-threatening.
• To diagnose an allergy, a clinician may take a blood sample.
• The symptoms of an allergy can be treated with drugs. However, the allergy itself requires desensitization.
• Anaphylaxis requires emergency treatment. Epinephrine injectors can help reduce the severity of an anaphylactic reaction.

What is an allergy?

Allergies are a very common overreaction of the immune system to usually harmless substances. 

When a person with an allergy comes into contact with an allergen, the allergic reaction is not immediate. The immune system gradually builds up sensitivity to the substance before overreacting.

The immune system needs time to recognize and remember the allergen. As it becomes sensitive to the substance, the immune system starts making antibodies to attack it. This process is called sensitization.

Sensitization can take a few days or several years. In many cases, the sensitization process is not completed. The patient experiences some symptoms but not a full allergy.

Allergies may also be seasonal. For example, hay fever symptoms can peak between April and May, as the pollen count in the air is much higher.

A study published in JAMA Pediatrics reported that food allergies in children cost the U.S. economy nearly $25 billion annually.

The number of people worldwide with allergies is increasing. 

Symptoms 

An allergic reaction causes inflammation and irritation. The signs and symptoms depend on the type of allergen. Allergic reactions may occur in the gut, skin, sinuses, airways, eyes, and nasal passages. 

Allergic reactions may be confused for other conditions. Hay fever, for example, creates similar irritations to the common cold but the causes are different.

Below is a range of various triggers and the symptoms they regularly cause in people who are allergic.

Dust and pollen

• blocked nose
• itchy eyes and nose
• runny nose
• swollen and watery eyes
• cough

Skin reactions

• flaking
• itching
• peeling
• rashes

Food

• vomiting
• swollen tongue
• tingling in the mouth
• swelling of the lips, face, and throat
• stomach cramps
• shortness of breath
• rectal bleeding, mainly in children
• itchiness in the mouth
• diarrhea

Insect stings

• wheezing
• swelling at the site of the sting 
• a sudden drop in blood pressure
• itchy skin
• shortness of breath
• restlessness
• hives, a red and very itchy rash that spreads across the body
• dizziness
• cough
• chest tightness
• anxiety
• possible anaphylaxis

Medication:

• wheezing
• swollen tongue, lips, and face
• skin rash
• itchiness
• possible anaphylaxis

Anaphylaxis

Anaphylaxis is a quickly escalating, serious allergic reaction that sets in rapidly. It can be life-threatening and must be treated as a medical emergency.

This type of allergic reaction presents several different symptoms that can appear minutes or hours after exposure to the allergen. If the exposure is intravenous, onset is usually between 5 to 30 minutes. A food allergen will take longer to trigger anaphylactic reaction.

Researchers reported in The Journal of Allergy & Clinical Immunology that the most commonly affected areas in anaphylaxis are the skin and respiratory system.

Symptoms of anaphylaxis include:

• hives all over the body, flushing, and itchiness
• swollen tissues
• a burning sensation
• swelling of the tongue and throat.
• a possible blue tint to the skin from lack of oxygen
• a runny nose
• shortness of breath and wheezing
• hoarseness
• pain when swallowing
• cough
• a drop in blood pressure that can speed up or slow down the heart rate 
• abdominal cramps
• diarrhea
• vomiting
• loss of bladder control
• pelvic pain similar to uterine cramps
• coronary artery spasm
• low blood pressure leading to high or low heart rate
• dizziness and fainting

For More information about allergy clinics in Qatar click here 

http://www.tabeebak.qa/clinics-list/category/allergy-treatment-clinics-in-qatar

For More information about allergy clinics in Qatar click here 

https://www.medicalnewstoday.com/articles/264419.php