There is no denying the fact that we all use cosmetics to make ourselves beautiful, and attractive. However, like every other good thing cosmetics too have side effects. There are various degrees of skin allergies produced by cosmetics. If the allergy is mild it might take weeks of regular use before you even notice it. However, strong allergies will appear on your skin in a matter of minutes after you apply the cosmetic product which doesn’t suit you.
Allergies are caused by the chemicals present in the cosmetics. If the chemicals are too strong then they tend to break your skin and thus establish direct contact with your flesh.
This is the reason you should always carry on a patch test before using any cosmetic product. Because that gives you the idea regarding which cosmetics your skin is allergic to and which you can safely use without the fear of rashes.