“Every Season can be Allergy Season, depending on what you’re Allergic to” – Clara Chung
Abraham Mathew Saji
Our immune system is responsible for defending the body against infections from micro-organisms, be it bacterial or fungal or viral in nature. In some cases, our immune system will fight against and defend our body from substances that typically don’t pose an infectious threat to the human body. These substances are known as allergens, and when our body reacts to them, it causes an allergic reaction. These allergens can trigger an allergic reaction to our body either by internal consumption, by inhalation or eating; or by external skin contact. Medical practitioners can also use allergens to diagnose and detect allergies, or can even inject them into the body as a form of treatment.
Causes of Allergies
The reason behind development of allergic reactions in some individuals has long been a subject matter of research by scientists. Genetics and hereditary factors seem to be one prominent cause. Another leading cause is environmental factors like weather, dust, pollen and fumes. Some of the food and medicines we consume internally; and external contact of certain substances too can trigger allergic reactions. Practically speaking, almost anything can cause an allergic reaction as allergic reactions are unique for each person.
Development of Allergies
Our immune system involves the white blood cells, which produce antibodies. When the body is exposed to an antigen (a foreign body such as pollen that can trigger an immune response), a complex set of reactions begins. The white blood cells produce an antibody specific to that antigen. This is called “sensitisation”.
The job of the antibodies is to help white blood cells detect and destroy substances that cause disease and sickness. These antibodies promote production and release of chemicals and hormones called “mediators”. Mediators have effects on local tissue and organs in addition to activating more white blood cell defenders. It is these effects that cause the symptoms of the reaction. Histamine is one of the better-known allergy mediators produced by our body. If the release of the mediators is sudden and extensive, the allergic reaction may also be sudden and severe. That is why some people will have a mild or severe allergic reaction immediately; for others, the same can take time to develop. Reaction time to allergens can vary among individuals.
Symptoms of Allergies
The symptoms of allergic reactions can vary from mild to severe. If one gets exposed to an allergen for the first time, the symptoms may be mild. These symptoms can get worse on repeated contact with the allergen. Symptoms of a mild allergic reaction can include hives (itchy red spots on the skin), itching, nasal congestion (known as rhinitis), rashes, itchy or irritating throat, watery or itchy eyes. Symptoms of a severe allergic reactions can cause abdominal cramping or pain, pain or tightness in the chest, diarrhoea, difficulties in swallowing, dizziness (vertigo), fear or anxiety, flushing of the face, nausea or vomiting, palpitations of the heart, swelling of the face, swelling of the eyes, swelling of tongue, weakness, wheezing, difficulties in breathing, unconsciousness.
A severe and sudden allergic reaction can develop within seconds after exposure to an allergen. This type of reaction is known as anaphylaxis and results in life-threatening symptoms, including swelling of the airway, inability to breathe, and a sudden and severe drop in blood pressure. When one experiences this type of allergic reaction, it is recommended to seek immediate emergency medical assistance as it can be fatal without treatment.
Common Types of Allergies
- Dust Allergy
The dust in our home may contain pet hair and dander, mould or pollen, spores, and dust mites or cockroach body parts and droppings, all of which are common allergens. These allergens can cause an allergic reaction when we inhale or come into contact with them. Dust allergies can cause breathing difficulties and may trigger asthma symptoms such as wheezing, coughing, tightness in the chest and shortness of breath. Dust also just makes some people itchy. People with dust allergies often suffer the most inside their own homes or in other people’s homes, than the outdoors. Oddly enough, their symptoms often worsen during or immediately after vacuuming, sweeping and dusting as the process of cleaning can stir up dust particles, making them easier to inhale and contact. - Mould Allergy
Moulds live everywhere, on logs and on fallen leaves, and in moist places like bathrooms and kitchens. Some people are allergic to these moulds. Mould allergies can be tough to outrun. The fungus can grow in the basement, in the washroom, in the cabinet under the sink where a leak went undetected, in the pile of dead leaves in the backyard or in the field of uncut grass down the road. There are so many species of moulds, most of which are not visible to the naked eye. As tiny mould spores become airborne, they can cause allergic reactions. - Cockroach Allergy
Cockroaches live in all types of buildings and all kinds of neighbourhoods. Cockroaches aren’t just unsightly pests, crawling across the kitchen floor in the middle of the night. They can be an allergy trigger as well. The saliva, faeces and shedding body parts of cockroaches can trigger both asthma and allergies. These allergens act like dust mites, aggravating symptoms when they are kicked up in the air. - Insect Sting Allergy
Stings from five insects, namely honeybees, hornets, wasps, yellow jackets and fire ants, are known to cause allergic reactions to the venom injected into the skin. While most people are not allergic to insect venom, the pain from a sting may cause them to mistake a normal reaction for an allergic one. The severity of an insect sting reaction varies from person to person. A normal reaction will result in pain, swelling and redness confined to the sting site. A large local reaction will result in swelling that extends beyond the sting site. - Pet Allergy
If your nose runs, your eyes water or you start sneezing and wheezing after petting or playing with a dog or cat, you likely have a pet allergy. A pet allergy can contribute to constant allergy symptoms, as exposure can occur at work, school, day-care or in other indoor environments, even if a pet is not present. Pets can produce multiple allergens that are found on the fur, dander, skin, saliva and urine. - Allergic Rhinitis
Allergic rhinitis is an allergic reaction to airborne allergens, like seasonal grass or ragweed pollen or year-round allergens like dust and animal dander. Allergic rhinitis is sometimes called “hay fever,” especially when caused by seasonal allergens. Hay fever shares many of the same symptoms as a common cold, but is not caused by a virus or bacteria. Instead, it is caused by your immune system reacting to allergens you breathe into your body.
Despite the name, hay fever is not necessarily a reaction to hay, and it does not cause a fever. There are two types of allergic rhinitis namely seasonal (symptoms can occur in spring, summer and early fall and are usually caused by sensitivity to airborne mould spores or to pollens from trees, grasses or weeds) and perennial (symptoms occur year-round and are generally caused by sensitivity to dust mites, pet hair or dander, cockroaches or mould. - Food Allergy
While any food can cause an allergic or adverse reaction, eight types of food account for over 90 percent of all reactions. These eight types of food are eggs, milk, peanuts, treenuts, fish shellfish, wheat and soy. One may wonder, “If we opt out of these food types, then what do we eat?” But as elaborated earlier, not all allergens cause the same level of reactions in every individual. While food allergies may develop at any age, most appear in early childhood. - Drug Allergy
People with drug allergies may experience symptoms regardless of whether their medicine comes in liquid, pill or injectable form. Reactions can occur in any part of the body. The time varies from person to person. Some people may react right away, while others might take the drug several times before they have an allergic reaction. Most of the time symptoms appear between 1-2 hours after taking the drug. Symptoms from a drug allergy can be like other allergic reactions and can include hives or skin rash, itching, wheezing, light headedness or dizziness, vomiting and even anaphylaxis. A combination of these symptoms makes it much more likely that it is an allergy than just nausea and vomiting on their own, which are common side effects of medications.
Treatment for Allergy
Long and short-acting antihistamines are usually the first line of therapy. Other adjuvant medications like decongestants, corticosteroids or anti-inflammatory medications may be prescribed as deemed necessary based on the manifestations by the healthcare practitioner.
Prevention of Allergy
The best way to prevent an allergic reaction is to avoid the substance that causes it, although this isn’t always easy or practical. With time, most people do not just learn to identify their allergy triggers, but also to avoid and manage them. One’s healthcare practitioner will also be able to help identify the allergy trigger factors by conducting certain skin and/or pathological tests. As the old adage goes, Prevention is better than Cure.
“Treatment without Prevention is simply Unsustainable” – Bill Gates.
References:
Allergic reaction testing, treatment and symptoms; Dec. 04, 2016; eMedicine Health; http://www.emedicinehealth.com/allergic_reaction/article_em.html; accessed July 04, 2017.
Allergies; Feb. 12, 2016; NHS Choices; http://www.nhs.uk/Conditions/Allergies/Pages.aspx; accessed July 04, 2017.
Peter J. Delves; Overview of Allergic Reactions; 2017 Merck Manual; http://www.merckmanuals.com/home/immune-disorders/allergic-reactions-and-other-hypersensitivity-disorders/overview-of-allergic-reactions; accessed July 04, 2017.
Abraham Mathew Saji is a pharmacist by qualification, engaged in research and development of medicines and their implications on the human body. He is an avid reader in pursuit of knowledge and understanding of technological advancements in the medical and pharmaceutical world. He is even more passionate about sharing his acquired knowledge, which he does by speaking at conferences, lectures and writing. He can be contacted at maz31abr@gmail.com for any clarification.
