What Causes Acne Scars?

There is a common theme in the three acnes. Pores are blocked; they burst, get inflamed, scar down, and heal.

Whether the patient (you, perhaps?) experiences acne vulgaris, acne rosacea, or acne inversa/hidradenitis suppurativa (AI/HS) depends upon variables that include lesion location, patient’s age, gender, family history, diet, sun exposure, and several others.

So let’s start at the beginning. With a look in the mirror.

How bad is it?

Staging and grading acne are essential in research but of little practical value in individual cases. If you’ve got it, you’ve got it.

Measuring it doesn’t make it better. Acne vulgaris that is “the end of my life forever” for one teen can be ignored by another.  rosacea can be embarrassing beyond belief and a huge social handicap, or a minor nuisance.

Acne inversa can be an occasion “boil” every few months, or it can be life-destroying. Be practical: If you’ve got it, and you want it gone, take the practical approach.


If you inherited the genes for any acne, like 90% of us, that’s unfortunate. Nothing fixes genes.

Be practical: You might want to choose a mate someday with their genes in mind if you want to look out for your children’s risk of acne.


We know acne is caused by the male hormone dihydrotestosterone (DHT). DHT works by linking to a male hormone (androgen) receptor.

It is like putting a key in the keyhole to open a door. The androgen receptor (keyhole) needs to be open to accept the key. Opening the keyhole requires insulin and/or insulinlike growth factor 1

Milk and milk products raise both insulin and IGF-1, opening the androgen receptor. Sugar also raises insulin levels, helping even more to open the androgen receptor.

 Foods that turn into sugar quickly (high-glycemicindex foods) also raise insulin levels. Milk and milk products also actually contain androgens (the keys to the keyhole)

Milk and milk products also actually contain other hormones that turn into androgens. So both dairy and sugary foods can open the androgen receptor. But dairy also supplies the androgens to turn on acne. Dairy is triple trouble

Be practical: Change to a truly natural diet. Eliminate all dairy. Go “low glycemic load.”


Hormones cause acne. No hormones=no acne. Eliminating hormones in either sex is not practical.

For males, hormone manipulation is used only rarely. Dutasteride is used in men with acne inversa. For females, hormones can be modified, replaced, and blocked. It is not natural, but it works.

Birth control pills with no- or low-androgen progestin are the best. Look for drospirenone, norgestimate, or norelgestromin.

Avoid all other progestins. Postmenopausal hormone replacement? Progesterone (oral) and estradiol patch only. Spironolactone blocks androgens and improves almost all acne in almost all women. Be practical: The acnes are hormonal disorders. Manage your hormones.


Stress is a contributor to the cause of acne. Stress also makes preexisting acne worse. But living a stress-free life is not practical for most of us. And we have no safe long-term stress-reducing medications.

Reducing stress is worth trying, as long as that effort is not stressful.

Yoga may be worth a try. Be practical: Eliminate the stress of looking in your mirror. How? Follow the other practical rules presented here. Comedones (plugs in pores) In acne vulgaris: Blackheads are plugged pores with open tops (Figure 0.1). Whiteheads are plugged pores with closed tops (Figure 0.2).

Both are called comedones (open and closed). One (of either) is a single comedo. Both grow until they empty themselves out or explode to the surface. In acne rosacea, the pores explode superficially before the plug is actually visible  .

In early acne inversa, the plugged pores are not prominent   The plugs tend to be deeper.

Blemishes—a brief catalogue


are small elevated bumps; they are usually red and often tender . If there is a collection of pus on top of a papule, it is a papulopustule. A collection of pus standing by itself at the opening of a pore is a pustule . If a pustule is at the top of a follicle, it is a folliculopustule.

Larger papules and larger papulopustules are nodules (Figure 0.10). These are battlegrounds. The enemy is the “stuff” caught in the pores. Acne is your body trying to get rid of this “stuff.”

So what is the stuff down in your pores? There are bacteria and yeasts and sometimes some little mites plus dead skin cells and hairs and irritating chemicals. Be practical: Use oral (isotretinoin) or topical retinoids to empty out the pores.

Eliminate yeast, bacteria, and other organisms. Empty out the lesion if and when practical.

Cool the inflammation with anti-inflammatory antibiotics. Use benzoyl peroxide to stop or limit the production of resistant bacteria. Use other anti-inflammatories like dapsone or steroids as necessary


Although common in acne inversa   and acne vulgaris, these also occur in serious acne rosacea.

These are raised or deep, red or purple bumps, and they are usually tender  . They occur anywhere on the body where folliculopilosebaceous units (FPSUs) exist.

They are sometimes crusted, draining, or bleeding (Figure 0.13). They are filled with inflamed material trying to reach the surface, heal, or scar down (Figure 0.14). In AI/HS, the ruptured nodules form a gelatinous material.

This invasive proliferative gelatinous mass (IPGM) invades and travels deep horizontally under the skin, producing sinus tracts  .

When the sinus tracts rupture and drain to the surface, they often become secondarily infected (Figure 0.16). Be practical: For acne vulgaris and acne rosacea nodules: Eliminate yeast, bacteria, and other organisms. Cool the inflammation with anti-inflammatory antibiotics. Start low-dose isotretinoin as soon as possible, whenever possible.

At the same time, get diet and hormones under immediate full control. If isotretinoin is impossible, use aggressive antiinflammatory therapy, including intralesional triamcinolone injections to minimize scarring. For AI/HS lesions: Use topical resorcinol cream to dry up small nodules.

Scars and sinuses

Scars and sinuses are caused by failure to treat acne early and properly. There is a genetic tendency toward scarring (Figure 0.17). Some people scar badly, even in spite of minor lesions and early care.

Others with the same degree of acne do not scar at all. Most acne scars are hypertrophic—raised above the original acne nodule (Figure 0.18). True keloid scars, spreading beyond the original nodule, are rare.