Normally, the sebaceous oil glands produce small amounts of sebum, whose job it is to moisten and protect the skin. In order to do this, sebum works its way up through the hair follicles, where it washes away dead cells that accumulate in the follicles. Then sebum empties onto the skin through tiny openings in the follicles called pores. Here sebum protects the skin from bacteria that live on the skin by washing the bacteria away.

However, when excess sebum is produced, it accumulates in the follicles rather than spilling out onto the surface of the skin. This occurs because the follicles are extremely small and narrow. Therefore, large volumes of sebum cannot pass through the follicles Page 11 to the surface of the skin at the rate the sebum is produced. Instead, sebum becomes trapped in the follicles, where it mixes with dead skin cells, forms sticky plugs that block the pores, and prevents sebum from reaching the surface of the skin. As a result, the skin around the clogged follicles dries out. At the same time, since not every follicle becomes clogged, excess oil that spills onto the skin through unclogged follicles causes the skin to feel oily.

Therefore, a person with acne may have dry skin around clogged follicles and oily skin everywhere else.

Worse yet, without sebum to wash away bacteria on the skin, bacteria grow and multiply around the clogged follicles. Eventually, bacteria get inside the clogged follicles, where they mix with sebum and dead cells and cause an infection. This most commonly occurs on the parts of the body that have the largest sebaceous glands, such as the face, chest, neck, shoulders, upper back, and buttocks. The result is the development of one type of acne lesion known as a comedone.

Since comedones do not contain pus, they are quite small. All comedones have either a white or black tip. Hence, comedones are commonly known as whiteheads or blackheads.

Blackheads, on the other hand, are closed comedones that continue to grow upward until they break through the skin’s surface. At this point, the enlarged hair follicle is visible and open to the skin’s surface. For this reason, blackheads are known as open comedones.

To the naked eye the contents of an open comedone look black. The black color is the result of oxidation, a process of discoloration that occurs when dead cells, sebum, and bacteria mix with oxygen in the air. However, some people mistakenly think that dirt trapped under the skin causes an open comedone to appear black. A young man recalls how this misconception affected him: “I had black-heads all over my forehead and nose. I scrubbed my face constantly, trying to scrub the dirt out of those blackheads. But I kept getting more. I couldn’t understand where all the dirt was coming from.”

Since comedones do not form as a result of severe inflammation, they are not painful, no matter whether they are blackheads or whiteheads. Moreover, because comedones are not large, red, or pus filled, when seen from a distance, the skin of people with comedones, especially those with whiteheads, appears relatively clear. However, because comedones are enlarged, clogged follicles, they do not disappear until the follicles unclog. This may not occur under normal circumstances until sebum production decreases or the patient receives effective acne treatment. Therefore, whiteheads and blackheads often stay on or under the skin for a long time.

Even more troubling, some closed comedones do not grow upward and become open comedones. Instead, as they become more and more packed with sebum, they grow downward under the surface of the skin and continue to enlarge until they burst. This results in the formation of more serious acne lesions such as papules and pustules.

Papules are small, firm, red bumps. They are only mildly inflamed because they form before pus has reached the area. Therefore, papules are more severe acne lesions than comedones, but milder than acne lesions that contain pus. However, because papules are inflamed, they are often tender to the touch.

As the inflammation worsens, the immune system sends pus to the area. When this happens, pustules form. Because pustules are caused by severe inflammation, they often feel hot and may be quite sensitive to the touch.

Not surprisingly, pustules are larger than papules. They are often about the size of the tip of a person’s little finger. Pustules are red at the base, with a yellowish, pus-filled inner region. A man who had pustules on his face, shoulders, and neck recalls: “They were big old welts filled with white poison and surrounded by red rings.”⁸

Although a pustule’s red base forms on the surface of the skin, the pus-filled core is near, but still underneath, the skin. However, as inflammation worsens and more pus is formed in the area, the pus-filled core of a pustule begins to swell like a balloon. When this happens, it is not uncommon for pustules to pop open and spill pus onto the skin. A man recalls: “In the morning before I went to school, I’d have big welts on my shoulders and neck. Sometimes at school they would break without me even knowing. When I got home I’d have stains on my shirt.”

Heat, redness, swelling, pain, and the presence of pus are all characteristics of inflammation, which in the case of acne appears on the skin in the form of papules, pustules, and cysts, other types of acne lesions.

The first type, comedonal acne, consists of whiteheads and black-heads alone, without the presence of other acne lesions. Therefore, comedonal acne is the mildest form of acne. However, since closed comedones often burst and become inflamed, it is not uncommon for people with comedonal acne eventually to develop papules and pustules.

When people have a mix of comedones, papules, and pustules, they have acne vulgaris, or common acne. A man who suffered from acne vulgaris recalls: “I had them all. I had blackheads on my nose. I had whiteheads on my forehead. I had bumpy red pimples and big pus pimples on my chin, neck, back, and shoulders.”¹⁰

Acne vulgaris is the most common form of acne, affecting approximately 90 percent of all people with acne. Acne vulgaris can be mild, moderate, or severe, depending on the number of acne lesions a person has and how severely the lesions are inflamed.

The third type of acne, cystic acne, is the most severe form of acne. The presence of comedones, papules, pustules, and numerous acne cysts characterize cystic acne. Because cysts are caused by severe inflammation and infection, cystic acne can be quite painful.

Making matters worse, if cystic acne is left untreated, the severe inflammation and infection that cause cystic acne can damage surrounding tissues. This frequently leaves the skin of people with cystic acne permanently scarred. A patient explains: “You can see the scars where I had cysts today. They look like little craters. You can see them on my neck and on my back. I’ve got a little bit of evidence on my face too. Wherever you see a crater, that’s where I had a cyst.”

Generally, oil production decreases after the age of seventeen. In most cases, as androgen and sebum levels decrease, so does acne. Thus, by the time most adolescents reach age eighteen, their acne symptoms begin to subside and disappear. However, approximately 30 percent of all adolescents with acne continue to be plagued with acne for the rest of their lives. According to acne expert and dermatologist Anthony C. Chu, “Acne can persist well into old age and I have a number of patients in their sixties, seventies, and even eighties who still have active acne. Acne is, therefore, not merely a teenage occurrence; it can affect you at any time of your life.”

Some women experience only occasional acne flare-ups. Since the female menstrual cycle causes hormone levels to rise and fall, many experts believe these flare-ups occur when lower than normal levels of the female sex hormone, estrogen, are being produced. Estrogen is known to counterbalance the production of androgen. Therefore, without sufficient estrogen, androgen production increases unchecked, leading to acne flare-ups. At other times, when estrogen levels are high and androgen levels are low, these women’s skin remains clear. Experts are unsure why this problem does not affect all women, but they theorize it is more likely to occur in women who, for unknown reasons, have the greatest fluctuation in their hormone levels.

Similarly, acne often flares up at different times during pregnancy as a pregnant woman’s hormone levels change in order to accommodate her body’s changing needs. Comparable hormonal changes often occur in some women after they give birth. As a result, some adult women develop acne shortly after their babies are born.

Chu describes how stress affects his patients: “I have looked after four women who have cancelled their weddings on at least one occasion. Each time they neared their wedding day, stress levels increased and their spots became so bad that they cancelled because they could not bear the thought of wedding photographs of themselves covered with spots.”