Contrary to popular belief, although allergic reactions to the environment and to the foods you eat are a frequent problem for many people, such reactions to other manufactured products you consume are rare.

Adverse drug reactions are more frequent; a breakout due to such a reaction is called an exanthem. For example, tetracycline and some other antibiotics will occasionally cause a reddening of the skin that may look like the start of acne. It isn’t, and it will go away either spontaneously while you are still on the medication, or definitely within a day or two after you stop.

Similarly, almost no cosmetics cause an allergic reaction. Both the individual ingredients and the formulated products are exhaustively tested, first on animals and then on humans. Once a new ingredient has been carefully tested, both on animals and on humans, its manufacturer usually defrays the cost of doing so by selling it to many different companies. They in turn, pleased with a new and presumably improved product, incorporate it into many different brands, which are then sold over the years to millions and millions of people.

Any product or ingredient that caused any noticeable level of allergic reaction would be promptly withdrawn from the market. Not only would its manufacturers be far too frightened of being sued to continue to sell it, but to do so would be unnecessary. Why sell an allergenic product when there are so many nonallergenic ones available?

No, there is very little chance that you will suffer from an allergic reaction to a medication, and virtually none that you will have such a reaction to a cosmetic. But even if you did, that reaction would not cause acne.

Having said that, as we have stressed elsewhere, cosmetic products that are greasy and occlude the skin do help to form the comedones that cause acne. Always use oil-free moisturizers.

Contrary to popular belief, although allergic reactions to the environment and to the foods you eat are a frequent problem for many people, such reactions to other manufactured products you consume are rare.

Adverse drug reactions are more frequent; a breakout due to such a reaction is called an exanthem. For example, tetracycline and some other antibiotics will occasionally cause a reddening of the skin that may look like the start of acne. It isn’t, and it will go away either spontaneously while you are still on the medication, or definitely within a day or two after you stop.

Similarly, almost no cosmetics cause an allergic reaction. Both the individual ingredients and the formulated products are exhaustively tested, first on animals and then on humans. Once a new ingredient has been carefully tested, both on animals and on humans, its manufacturer usually defrays the cost of doing so by selling it to many different companies. They in turn, pleased with a new and presumably improved product, incorporate it into many different brands, which are then sold over the years to millions and millions of people.

Any product or ingredient that caused any noticeable level of allergic reaction would be promptly withdrawn from the market. Not only would its manufacturers be far too frightened of being sued to continue to sell it, but to do so would be unnecessary. Why sell an allergenic product when there are so many nonallergenic ones available?

No, there is very little chance that you will suffer from an allergic reaction to a medication, and virtually none that you will have such a reaction to a cosmetic. But even if you did, that reaction would not cause acne.

Having said that, as we have stressed elsewhere, cosmetic products that are greasy and occlude the skin do help to form the comedones that cause acne. Always use oil-free moisturizers.