Allergies can be caused by different environmental factors

Inhalants: pollens, flowers, perfume, dust, paint, formaldehyde etc

Ingestants: food, drinks, vitamins, drugs, food additives

Contactants: fabrics, chemicals, cosmetics, furniture etc

Injectants: insect bites, stings, injectable drugs, immunisation etc

Infectants: viruses, bacteria, fungal

Physical agents: heat, cold, humidity, dampness, fog, wind, dryness, sunlight

Genetic factors: inherited illnesses or tendency from parents, grandparents

Moulds and fungi: moulds, yeast, candida, parasites etc