Acne is caused by eating certain foods

This one has been around a long time yet is supported by exactly no scientific proof.  Although certain individuals may seem experience outbreaks when they eat certain foods, there is no universal laws that apply to everyone.  Eating pizza, chocolate, nuts, and greasy foods will not increase your acne.

Acne is related to dirt or having dirty skin

Although having clean skin has other benefits, dirt does not cause acne.  Acne is formed under the surface of the skin and is due to build-ups of sebum and dead skin cells.  It's not dirt that clogs your follicles.

Washing your face all the time will clear up acne

Having clean skin is not the answer to preventing acne.  Overdoing it as far as washing your face can actually make matters worse.  Stripping your skin of oil could lead to future breakouts.

Only teenagers get acne

It is true that 9 out of 10 teenagers experience acne, but it is also true that about 1 in 4 adults get it also.  Acne seems to be connected with hormones which would explain why teenagers have such a high incidence of acne, but adults are also going through hormonal changes at various times in their lives.

Stress causes acne

Scientific evidence shows that stress is not that large of a factor in acne.  It was believed for many years that stress caused bouts of acne but it simply isn't so.

Acne can be cured

Many people view acne as a disease that can be permanently cured.  Unfortunately, this isn't the case.  Acne can be controlled and prevented through proper skin care, but it cannot be cured.