During the past two decades, there has been a rise in the prevalence of food allergy (FA), signifying a second wave of the allergic epidemic. FA imposes significant individual, social, and economic burdens.
Changes in the environment, increased urbanization, global warming, decreased exposure to early life infections and changes in lifestyle and diet; all play their part in the development of food allergy.
Although more than 170 foods have been recognized as potential allergens, a small subset comprising peanuts, tree nuts, fish, shellfish, milk, egg, wheat, soy, and sesame seeds, predominantly account for the majority of allergic reactions.
The prevalence of food allergies, as determined through food challenges, is reported to be 0.6% for cow’s milk, 0.2% for egg, 0.1% for wheat, 0.3% for soy, 0.2% for peanut, 0.5% for tree nuts,0.1% for fish, and 0.1% for shellfish, varying across different geographical regions.
In some developed countries, 1 in 10 infants has challenge-proven immunoglobulin (IgE)-mediated Food allergy. By the year 2024, food allergy rates in the United States are 8% among children and 11% among adults.
There is a high co-occurrence of FA with other atopic diseases including atopic dermatitis, allergic rhinitis, asthma, and eosinophilic esophagitis etc.
Approximately 30% of children experience allergies to multiple foods. Lipid Transfer Protein (LTP) allergy has emerged as the leading cause of primary food allergy and food-induced anaphylaxis in older children and adults.
It is necessary for a high-risk patient to be aware of the foods causing allergic severe immunological reaction.
Great advances have been achieved in allergy diagnostic tests (specific IgE-extract based, Component Resolved Diagnosis-CRD, Basophil Activation Test-BAT, and mast cell activation test-MAT).
The primary approach to managing the condition remains avoiding the triggering food; however, this does not decrease the likelihood of unintentional allergic reactions.
There is a growing body of evidence which supports that specific oral tolerance can be achieved by combining oral immunotherapy (OIT) with biological (omalizumab).
DIAGNOSIS
An accurate diagnosis is a fundamental step in management of food allergy.
- History and physical examination
- Skin prick test and Prick-prick test
- In-vitro test
- Extract-based specific IgE
- Component Resolved Diagnosis (CRD)
iii. Basophil activation test (BAT)
- Oral food challenge (OFC)
FOOD ALLERGY-MANAGEMENT
Prevention of Food Allergy
Maternal Diet in Pregnancy and During Breast Feeding (BF)
- Maternal antigen avoidance diet as maternal dietary proteins are transferable into breast milk but mothers should be encouraged to continue breastfeeding for a minimum of six months.
- Diet indices -dietary factors that suppress FA are found in cruciferous vegetables (cabbage, Brussel sprouts, broccoli) or oat, rice and nuts
- Nutrients / vitamin D / pre and probiotics, Calcium supplement antioxidants
Infant Diet
- Breast-feeding and formula feeding-Breastfeeding is the first choice for all infants including those with food allergy.
- Microbiome- Microbial treatments are currently in the works for addressing food allergies, either as independent therapies or in conjunction with oral immunotherapy (OIT).
- Micronutrient / vitamin D/ omega-3 fatty acids- Vitamin D deficiency is associated with food allergy.
- Solid food should not be introduced before four months.
Elimination Diet
It is the best means of controlling for the variability of chronic disorders (e.g., Chronic urticaria, atopic dermatitis, occupational bronchial asthma etc.).
- The least antigenic cereal is rice, oat, corn, buckwheat
- Vegetables without peel and seeds
- Fruits: without peel and seeds
- Pulses: each pulse to be repeated every 72 hours
Travelling with Food Allergy
- Check travel insurance.
- Check airline policies in advance, particularly for international travel.
- Prepare and carry ASCIA action plan for Anaphylaxis and ASCIA Travel plan (these can be completed by general practitioners).
- Informing airlines and travel attendants.
- Other strategies:
○ Carry your own food.
○ Wipe down tray tables.
○ Food exclusion zones- some airlines have food exclusion zones as part of their management policy.
Allergen Immunotherapy
Currently, oral immunotherapy stands out as the most extensively researched method for addressing food allergies.
Immunotherapy, a type of therapeutic intervention, involves the utilization of a substance to alter the immune response in the treatment of a disease explore the potential use of four types of allergen immunotherapy in treating food allergies:
subcutaneous immunotherapy (SCIT),
oral immunotherapy (OIT),
sublingual immunotherapy (SLIT) and epi-cutaneous immunotherapy (EPIT).
Studies have shown good results of SCIT in pollen associated food allergy; SLIT in peanut, hazelnut and peach induced FA; OIT in milk, hen’s egg, and peanut allergy.
Emergency action plan (epinephrine auto-injector) is recommended as a guide
during serious life-threatening symptoms of allergy (angioedema,anaphylaxis).
Active disease-modifying therapy immunotherapy with biological agents has been studied in recent years.
In an era of omics and artificial intelligence it is expected that combinations of old and new biomarkers will further improve diagnostic accuracy and treatment.
Citation: P.C. Kathuria, Manisha Rai. Food Allergy-practical Approach. Research & Reviews: A Journal of Immunology.