Most people experience acne in their teenage years but the truth is, it can persist into your 30's, 40's, and even into your 50's, dermatologists refer to this as persistent acne.
Having acne at the age of 40 or 50 can be very frustrating especially when the acne treatments that worked in the teenage years are no longer effective.
So, what causes acne in adults?

1. Stress - studies show that during times of stress the body begins to produce elevated levels of androgens (a type of hormone).
   These hormones stimulate the sebaceous glands, the glands attached to hair follicles that produce sebum, which is an oily substance that keeps the skin moisturized.
   
2. Hair and skin products - many skin and hair products on the market contain oils which promote a type of acne called acne cosmetica.
   When you shop for sun screens, hair sprays, or skin lotions, be sure they are oil free products.
   They will have one of the following on the label, "oil-free" "non-comedogenic" or "non-acnegenic.
   "
3. Hereditary - researchers have found that if you had a parent or grand parent as well as aunts or uncles that have had severe acne problems you would be likely to develop acne as well.
   
4. Side affect of medications - if have recently started taking a prescribed medication for another medical condition then began to develop pimples, there is a good possibility that the acne can be a side affect of the medication.
   Absolutely do not stop taking the medication instead, speak with your doctor to see if there is an alternative medication.
   If there is not an alternative medication see a dermatologist for an acne treatment that will control it until you no longer need to take the other medication.
   
5. Fluctuations in hormones - this is mainly prevalent in women, just as with hormonal swings in puberty, they occur in adult women as well.
   Some women will have a breakout once a month, and many, a breakout during pregnancy.
   These breakouts are being caused by hormonal fluctuations that accompany pregnancy and the short period during a woman's menstrual cycle.
   Birth control pills that contain both estrogen and progestin help keep acne in check when they stop taking them the acne flares up.
   Birth control pills that contain only progestin may not help to keep acne in check.
   
6. Underlying medical conditions - once again pertaining to women, if you suffer a breakout of acne and it is accompanied by thinning hair or bald spots on the scalp, excessive facial hair, and irregular menstrual cycles, it could be a sign of polycystic ovaries or adrenal hyperplasia.
   Polycystic ovaries are a condition that causes cysts to grow on the ovaries, and adrenal hyperplasia is a disorder of the adrenal gland.
   

If you believe your acne is being caused by an underlying medical condition such as, in the number six cause above, you should see your physician immediately for proper treatment of the underlying cause.
If on the other hand it is being caused by any of the other causes then, treatment can effectively control and clear up the acne problem you face.
However, many never seek treatment options because they believe there are no treatment options available.