Are allergies contagious? what are some contagious illnesses?

No: Allergies are your body's unique reactions to allergens that your body recognizes as foreign to your system. If it is an inhaled allergen, it would cause sneezing and watery nasal discharge. If it is an allergen that settled on the skin, it would cause a rash that is generally itchy. It is not contagious but rather genetic so it is common for members of family to react to same antigen.

No. Very long list.: Allergies are not contagious although there is a genetic component to allergy and there are clearly "allergic" families. The following contagious diseases are huge in the developing world: cholera, malaria, dengue fever, influenza, typhoid, measles, hepatitis a/b/c, onchocerciasis, leishmania, shigella, salmonella.

Allergies: Allergies are not contagious but many viral, bacterial, fungal and parasitic infections are.