The two main types of contact dermatitis are:
Allergic contact dermatitis: Your body has an allergic reaction to a substance (allergen) that it doesn’t like. Common allergens include jewelry metals (like nickel), cosmetic products, fragrances and preservatives. It can take several days after exposure for an itchy, red rash to develop.
Irritant contact dermatitis: This painful rash tends to come on quickly in response to an irritating substance. Common irritants include detergents, soap, cleaners and acid.