Core Framework & Diagram Eosinophils: The Parasite Killers

From a hygiene hypothesis perspective, this is interesting. Large-scale deworming programs have been observed to coincide with rising allergy rates in some populations. This isn't an argument against deworming — but it supports the hygiene hypothesis view that parasites were once 'old friends' that helped maintain immune balance. The public health gains from eliminating parasitic infections may come with the side effect of increased allergy rates.

Fundamental treatment (rather than just symptom control) is specific immunotherapy (desensitization) — gradually increasing allergen exposure doses to retrain the immune system toward tolerance (shifting from Th2 toward Th1/Treg responses). Treatment usually takes three to five years but can produce lasting or permanent symptom improvement in many patients. Medications (antihistamines, corticosteroids, biologics) effectively control symptoms but don't change the immune mechanism.

Food allergy is immune-mediated, involving IgE antibodies and mast cell/eosinophil activation — it can trigger hives, angioedema, laryngeal edema, and anaphylaxis, with symptoms appearing within minutes to two hours of eating. Food intolerance (like lactose intolerance or gluten sensitivity) doesn't involve IgE or immune cells — it's usually a digestive enzyme deficiency or gut sensitivity issue producing primarily digestive discomfort, without severe systemic reactions.

Some do, some don't. Milk and egg allergies are most common in childhood and approximately 80% of children develop natural tolerance before age five. Peanut and tree nut allergies are more persistent, with only about 20% naturally resolving. Respiratory allergies (pollen, dust mites) are typically most symptomatic around puberty and may improve or persist into adulthood. Regular follow-up and oral food challenges are the standard method for determining whether tolerance has been achieved.