Inhalants: grasses, pollens, flowers, perfume, dust, paint, formaldehyde, smoke, fumes, pollution, etc.
Ingestants: food, drinks, vitamins, drugs, food additives etc.
Contactants: fabrics, chemicals, cosmetics, furniture, utensils etc.
Injectants: insect bites, stings, injectable drugs, vaccines, immunization etc.
Infectants: viruses, bacteria, contact with infected persons etc.
Physical Agents: heat, cold, humidity, fog, wind, dryness, sunlight, sound, etc.
Genetic Factors: Inherited illness or tendency from parents, grandparents, aunts, uncles, great grandparents etc.
Molds and Fungai: Molds, yeast, Candida, parasites etc.
Emotional Factors: painful memories of various incidents from past and present.