Environmental & Food Allergies
What are Environmental and Food Allergies?
Allergies are hypersensitive immune responses to substances that are typically harmless to most individuals. These allergens can be present in the environment or ingested through food. Environmental and food allergies are becoming increasingly common, affecting people of all age groups and significantly impacting the quality of life.
Environmental Allergies
Environmental allergies occur when the immune system overreacts to airborne substances such as pollen, dust mites, pet dander, mold spores, and pollutants. These reactions are typically seasonal (e.g., pollen) or perennial (e.g., dust mites).
Common environmental allergens are
- Pollen: This is from trees, grasses, and weeds; commonly causes hay fever or allergic rhinitis.
- Dust Mites: These are microscopic organisms that thrive in bedding, upholstery, and carpets.
- Pet Dander: They are microscopic skin flakes from cats, dogs, and other animals.
- Mold Spores: These are found in damp environments like bathrooms and basements.
- Smoke and Pollution: Though they are not allergens they can aggravate allergic symptoms.
Causes of Environmental Allergies
Some of the common causes of environmental allergies are:
- Genetic tendency (atopy)
- Immune system overreaction to harmless particles
- Prolonged exposure to allergens (e.g., pollen, dust, mold, pet dander)
- Air pollution and cigarette smoke
- Indoor humidity promoting mold and mites
- Hygiene hypothesis (limited exposure in early life)
Clinical Features of Environmental Allergies
Environmental allergies generate the following symptoms:
- Sneezing
- Runny or congested nose
- Itchy eyes, nose, or throat
- Watery eyes
- Cough and postnasal drip
- Asthma exacerbations in sensitive individuals
Diagnosis of Environmental Allergies
Environmental allergies can be diagnosed based on your detailed clinical history and some test by your healthcare provider including:
- Skin prick tests
- Serum-specific IgE tests
- Nasal smear (to check for eosinophils)
Management of Environmental Allergies
Environmental allergies can be avoided with the following precautions:
- Allergen avoidance (e.g., using air filters, dehumidifiers)
- Antihistamines and nasal corticosteroids
- Leukotriene receptor antagonists
- Immunotherapy (allergy shots or sublingual tablets) in selected cases
Food Allergies
Food allergies are immune-mediated reactions that occur shortly after eating specific foods. Unlike food intolerances, food allergies can cause systemic and potentially life-threatening reactions.
Common Food Allergens:
- Milk
- Eggs
- Peanuts
- Tree nuts (e.g., walnuts, almonds)
- Fish and shellfish
- Soy
- Wheat
Types of Food Allergic Reactions:
IgE-mediated reactions: This has rapid onset, and includes anaphylaxis
- Non-IgE-mediated reactions: In this type, we can see delayed onset, and it may involve gastrointestinal symptoms
- Mixed-type reactions: It has features of both mechanisms
Causes of Food allergies
Some of the causes of food allergies includes:
- Family history of allergies
- Immune system mistakenly reacting to food proteins
- Gut microbiome imbalance (dysbiosis)
- Delayed exposure to allergenic foods in infancy
- Processed foods and preservatives
- Cross-reactivity with environmental allergens
Symptoms of Food Allergies
Food allergies have following symptoms:
- Hives, itching, or eczema
- Swelling of lips, face, tongue, or throat
- Abdominal pain, diarrhea, nausea, or vomiting
- Wheezing or shortness of breath
- Anaphylaxis (life-threatening emergency)
Diagnosis of Food Allergies
Food Allergies can be diagnosed based on the patient’s detailed medical and diet history and also your healthcare providers may order a few investigations including:
- Elimination diet and food challenge
- Skin prick testing
- Serum IgE testing
- Atopy patch testing (for non-IgE-mediated reactions)
Management of Food Allergies
Food Allergies can be managed by:
- Complete avoidance of known allergens
- Use of epinephrine auto-injectors for anaphylaxis
- Education on reading food labels and emergency management
- Dietitian support to ensure nutritional adequacy
Prevention of Environmental and Food Allergies
Some of the preventive measures to avoid environmental and food allergies include:
- To educate patients and caregivers about allergen avoidance strategies.
- Encouraging early recognition of symptoms.
- Promoting timely intervention and emergency preparedness, especially in cases at risk of anaphylaxis.
- Considering early introduction of potential allergens during infancy (as per current guidelines) to reduce allergy risk.
