An allergic reaction occurs when the body’s immune system reacts normal particles which are usually harmless (also known as allergens). Whilst these substances do not usually cause any issues, in individuals who have allergy, their body defense system sees this allergen as threat and mount a response against these particles.
Common allergens include:
- Protein produced by house dust mites
- Food such as peanut, milk, eggs, tree nuts
- Insects such as bees and wasps
Allergy is more common in people with atopy (genetically more prone towards allergy), positive family and personal history of allergic rhinitis, eczema and asthma.
Allergic reaction is triggered when a person is in contact with an allergen, the body recognizes the allergens and triggers an defense response. This leads to the release of a substance known as histamine. Histamine can induce inflammation, swelling, and itching making one feel uncomfortable.
Allergy Response Involves Various Organs of the Body
In the respiratory tract, one can present with sneezing, runny nose, coughing, wheezing, breathlessness. There is a strong association of allergy with allergic rhinitis and asthma.
In the gastrointestinal system, an allergic response can trigger nausea, vomiting, abdominal pain and cramps, or diarrhea.
Allergy Response in the Skin
In the skin allergy, one commonly presents with eczema, swelling in particularly over the gravity dependent areas such as the eyes, lips, mouth (angioedema) and developes nettle-like rashes (hives). These 3 conditions are further discussed in separate individual articles.
Severe Allergic Reaction
Sometimes, the allergic reactions can be very serious and even be life-threatening. This a condition known as anaphylaxis. This usually occurs within minutes to hours where one is exposed to allergen, and presents with acute breathlessness, wheezing, throat swelling, lip and mouth swelling, puffy eyes, rashes, and drop in blood pressure. Those who has a history of anaphylaxis should always carry an emergency adrenaline pen injection known as Epipen. It is a complete reversible condition, yet one can succumb to the condition if delay seeking treatment.
How can I test for Allergy?
Allergy to specific allergens can be detected via blood tests or skin prick test. Your doctor will discuss with you on the pros and cons of each tests and which option is suitable to individual concerns and condition.
RAST Blood Test:
RAST Blood test is used to detect IgE antibodies that are produced against certain allergens. Currently, there are multiple range of allergen panels that can be tested through IgE antibodies blood tests.
Skin Prick Test:
Skin prick test is a procedure performed over the inner forearm or upper back of a patient. It involves introduction of allergens into the skin via small sterile needles that penetrates the skin surface. The tested area of the skin will be marked and the skin will be pricked with small drops of different allergens. Most patients tolerate the test well with minimal discomfort. Your doctor will review the tested area of the skin, monitor for any evidence of redness, bumpy swelling, and measure the size of swelling (if any). If you are sensitive towards a particular allergen, you may experience mild redness and itchiness over the tested area.
How Safe is Skin Prick Test:
The test is offered in clinic setting with close monitoring from your health care providers. Severe reaction to skin prick test is uncommon.
Skin prick test is not suitable for
Those with history of anaphylaxis to that particular allergens
People with severe skin inflammatory conditions that affect most areas of their skin such as eczema or psoriasis
One that is on oral antihistamine and is not able to stop prior skin prick test
What are the Treatment Options for my Skin Allergy?
- Avoidance of the culprit allergens
- Adequate moisturizer. Consider soothing calming moisturizing cream
- Antihistamine to ease the irritation, itch, inflammation and swelling
- Steroid to reduce hypersensitivity, inflammation and swelling
- Introducing Immunotherapy. This works by desensitizing and down-regulating the body
- immune system against specific allergen. It is feasible by repeated regular small exposure to specific allergen. Immunotherapy can be administered by sprays underneath the tongue (Sublingual sprays)
What can I do if I have Skin Allergy?
- Write a diary on where and when a reaction occurs
- Reduce the risk of an allergic reaction by avoiding the allergen wherever possible
- Speak to your doctor, to understand the treatment options available