Overview of allergies
Allergy is the general non medical term for a hypersensitivity reaction. It is a reaction of the body’s immune system in response to stimuli or a trigger factor. These trigger factors are termed allergens (substances causing allergy). The allergen can be anything – some types of food, pollen, medicines, dust mites, pet dander etc. The only criteria for a substance to be termed as an allergen is it’s ability to cause an allergy. Asthma is one of the common allergic conditions that is a significant public health problem, with alarming trends in prevalence, morbidity, and mortality1. In this condition, there is inflammation of the airway in response to an allergen, causing restricted air entry into the lungs. Allergic response to dust mites, pollens and seafood are some of the common allergic conditions affecting the population.
Allergies - Seasonal and Perennial
Allergies can be either perennial or seasonal. As the name suggests, seasonal allergies appear only at a certain time of the year. The reason could be the variation in the temperature, humidity etc. that can trigger the allergy symptoms. On the other hand pollination in certain plant species happen at a certain time of the year that can lead to higher allergy symptoms during that period. On the other hand perennial allergies happen throughout the year. They are not in any way related to any season or time period. These can be like food allergies, pet dander allergies, drug allergies etc.
How does an Allergy Develop?
Unlike common belief, allergy develops through stages. It is commonly believed that genetics plays a significant role in a person’s susceptibility to develop an allergy. Genetic variation provides the basis for differences in a person’s response to a variety of environmental factors that can help in the development of an allergy2,3. With the presence of the genetic factors and other environmental factors, an individual becomes sensitized to certain substances. During subsequent exposures of the individual to the allergens the allergic response increases in severity.
Signs and Symptoms of an Allergy
The signs and symptoms of an allergy can be as simple as a skin rash and/or itchiness to as severe as an anaphylactic shock leading to death.
Allergic reactions can present singly or in a combination of any of the following
- Urticaria- itchiness, skin rash
- Angioedema- swelling of the eyes, lips and/or tongue
- Asthma – respiratory symptoms (wheezing, breathlessness)
- Anaphylaxis – full system response. Can prove fatal, if unattended.
In any case, prompt medical attention is required to reduce the severity of the reaction. In some conditions like allergic reactions to drugs, the condition may lead to swelling of the tongue, leading to closure of the respiratory tract proving fatal.
As a general rule, a person hypersensitive to one substance can be hypersensitive to other substances also and thus must exercise caution during intake of new drugs, food etc. It is better to take the new substance in a smaller quantity to assess if a hypersensitive reaction develops.
Allergy - Treatment Options
The first stage of treatment is to identify the allergen and try to prevent exposure to it. There are various treatment options available for treatment or symptomatic relief of allergy depending upon the severity.
In many of the conditions allergic reactions can be prevented. Especially for conditions like asthma, prevention at home forms a significant part of the management2.
If the allergen cannot be identified clearly, the first step towards prevention of an allergy reaction is to go for allergy testing.
It is a procedure performed at a specialized laboratory. The purpose is to find the exact substance for which the person is hypersensitive to and avoid getting exposure to that substance.
The National Asthma Education and Prevention Program Expert Panel guidelines for the management of asthma recommend that patients who require daily asthma medications have allergy testing for perennial indoor allergens and that, when triggers are found, exposure to allergens and pollutants be controlled through avoidance and abatement2.
The prevention method is mostly dependant on the type of allergen. If it is airborne like dust mites, pollens, etc., use of a powerful air filter inside the house can lead to reduction of attacks. For food allergies, the rule is to avoid the food.
You May Also Like To Read
1.Richard J. Scarfone, Joseph J. Zorc, Geoffrey A. Capraro. Patient self-management of acute asthma: adherence to national guidelines a decade later. Pediatrics. 2001; 108 (6): 1332-1338.
2.Steinke JW, Rich SS, Borish L. Genetics of allergic disease. J Allergy Clin Immunol. 2008;121 (2 Suppl) :S384-7.
3.Kiyohara C, Tanaka K, Miyake Y. Genetic Susceptibility to Atopic Dermatitis. Allergol Int. 2008; 57 (1): 39-56.
4.Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. National Asthma Education and Prevention Program. National Heart, Lung, and Blood Institute. Full report 2007.