4 minute read
Allergies
Despite a significant rise in awareness of allergies in recent years, plenty of confusion still surrounds them. The mechanism behind allergy is complex but is best described as the negative reaction that the body has to a particular substance. Allergies are either seasonal (eg, caused by tree and plant pollen) or nonseasonal (eg, caused by dust). Mold, animal dander, dust, and pollen are the most common allergens. Very often these substances are foods, although a person can be allergic to pretty much anything. Common allergens other than food include Latex, bee and wasp stings, and a number of medicines (e.g. antibiotics, NSAIDs, aspirin, chemotherapy drugs).
SYMPTOMS
Like an unwelcome guest, many allergens arrive with little warning. Their most common effects are all too familiar to the millions suffering from allergies. Symptoms are broad and depend on which part of the body is affected. For example, hay fever (also known as seasonal allergic rhinitis, because it is mainly triggered by pollen) affects the eyes and nose, causing sneezing, a runny nose, and, sometimes, a stuffy, blocked nose.
Respiratory Symptoms
Sneezing/ Runny Nose - Perennial allergic rhinitis (a condition that causes symptoms all year round) often causes a stuffy, blocked nose.
Asthma - Asthma affects the respiratory system causing wheezing (a whistling sound in the chest), breathlessness, chest tightness and a cough.
Dermatological Symptoms
Eczema - (also called dermatitis) can affect the skin causing itchy, red rashes. Allergic contact dermatitis - (a condition which is caused by the skin coming into contact with an allergen, such as nickel) is characterised by red, scaly skin that itches where it has made contact with the allergen. Allergies to some foods, bites or stings can cause urticaria (itchy blisters and red patches on the skin).
REVIEW
There are various theories as to why allergy incidence is increasing so rapidly. These include:
Hygiene hypothesis. This argues that, if we are not exposed to bacteria and endotoxins in early childhood, our immune systems don’t develop as they should and therefore overreact when exposed to allergen challenges Excessive use of antibiotics
Insulation and double-glazing, which have created more of an allergy challenge within people’s homes. Although patients may attempt to avoid allergens’ triggers, they may be unaware of exacerbating environmental conditions, including aerosol sprays, air pollution, cold temperatures, humidity, irritating fumes (including perfume), tobacco and wood smoke, and poor housekeeping
DIAGNOSIS
Although most people are aware of seasonal allergies, many cannot pinpoint the culprit. Keeping a log regarding symptom onset, time of day, and environmental surroundings helps narrow the list. Patients’ symptoms often vary in intensity from day to day, further complicating assessment. Patients with ongoing allergies should see a specialist, even if symptoms are mild. The intensity of current allergic reactions does not necessarily predict the intensity of future attacks.
FOOD TOLERANCE AND FOOD ALLERGIES
Many people confuse food allergies with more common food intolerances. Allergies involve an immune reaction; food intolerances stem from the inability to digest certain foods. Symptoms are similar, but milder: gastrointestinal problems, hives, itching, or eczema. Although avoiding specific foods is the recommended strategy, patients should be evaluated by an allergist. Symptom recognition in food allergy is an important aspect of patient education, so the patient knows when to use an adrenaline auto-injector. This is as important as knowing how to use it.
Discuss anaphylaxis
Those with severe reactions have increased risk for anaphylaxis. Inform patients they need to go to A&E if: acute symptoms occur within minutes or hours involving respiratory compromise, tongue swelling, or hypotension skin tone is flushed or pale (almost always present with anaphylaxis)
nausea, vomiting, or diarrhea begins dizziness or fainting, or a weak or rapid pulse, occurs. Certain medications (especially penicillin); foods like peanuts, fish, shellfish, milk, and eggs; and insect stings are common triggers for anaphylaxis.
TREATMENTS
The choice for treating allergic rhinitis can be confusing. Pharmacists are well placed to recommend a product that is matched to symptoms and their severity. It is beneficial to start treatment before symptoms begin. Eye Drops - Eye symptoms are common in allergic rhinitis, with patients reporting red, watery and itchy eyes in addition to nasal symptoms. If this is the case, eye drops may be required. Antihistamines - These products are the first line of defence for many allergic conditions. When helping patients choose an antihistamine, it is important to be aware of the sedative effect of first-generation drugs, as well as the short duration of action. The benefit of second-generation antihistamines is the rapid onset, which is good for compliance, as is the daily dosing and the fact that they are non-sedating. On occasion, patients may require high doses of antihistamines to manage allergic or potentially non-allergic symptoms – eg in chronic spontaneous urticaria. Although these doses should be prescribed, it is important to provide reassurance that they are safe and within national guidelines.
