Why do allergies develop in an otherwise healthy person

Why do Allergy develop in an otherwise healthy person https://youtube.com/shorts/Yv6pkPzpSZg?feature=share

Why Allergy develops in an healthy

A change in environment can tip the balance:

• Moving house / workplace

• Seasonal variation (pollens, especially in India like Prosopis, Parthenium)

• Indoor changes (dust mites, mold, pets)

Respiratory infections can alter the immune response

• Post-viral airway hyperreactivity

• Increased permeability → allergen sensitization

Adult develops allergic rhinitis or asthma after a viral illness

Hygiene Hypothesis / Microbiome Changes

Reduced microbial exposure → immune dysregulation

• Urban lifestyle

• Excess antibiotic use

• Reduced gut microbiome diversity

Hormonal Influences

• Pregnancy

• Thyroid dysfunction

• Menstrual cycle changes

These can modulate immune response and unmask allergies

Age-related Immune Changes

Even adults can develop new allergies:

• Immune regulation shifts over time

• Loss of tolerance to previously tolerated allergens

Pollution & Environmental Factors

• Air pollutants damage airway epithelium

• Increase allergenicity of pollens

Relevant in Indian cities:

• Diesel exhaust particles enhance IgE response

Genetic Predisposition (Underlying baseline)

Even if asymptomatic earlier:

• Atopic individuals may express disease later

• Family history often present but not always obvious