Acne 101 – Skin Rocks

Acne 101

What is acne?

Acne is one of the most common disorders of the skin, affecting approximately 85% of us at some point in our lives. We are most likely to develop it during adolescence, triggered by the production of sex hormones known as androgens at the onset of puberty. 

Acne subsides by the early twenties in many cases, however, it can persist into adulthood (over 25) and late-onset acne can also occur. Current research indicates that the number of adults with acne is on the rise.

Although acne is common, the intensity and duration varies widely from one person to another, and no two journeys are alike. 

What causes acne?

There are four primary factors that interact to cause acne: 

  1. Excess sebum production by sebaceous glands. These are the tiny oil-producing glands that sit alongside our hair follicles.
  2. Build-up of dead skin cells inside the hair follicle. These cells mix with sebum forming a blockage or “plug” that obstructs the opening of the hair follicle (pore). If this blockage occurs near the surface of the skin, exposure to air causes the mixture to turn black. This is what gives “blackheads” their characteristic appearance.
  3. Cutibacterium acnes. This bacteria lives on the skin and thrives in airless, oily conditions like those found in hair follicles. It turns sebum into fatty acids, deactivating enzymes that normally put the brakes on inflammation.
  4. Release of inflammatory mediators. Once the brakes are off, cascades of chemicals are produced by skin cells, leading to the type of inflammation that causes acne.

What are the risk factors for acne?

  1. Genes are likely to be involved in acne predisposition. Lending weight to this theory, there are high rates of concordance amongst identical twins (meaning that if one twin has acne the other is extremely likely to develop it as well). There is also a tendency towards severe acne in people with a positive family history. 
  2. Hormones. Our sebaceous glands are under hormonal control. In people who have acne, the glands are particularly sensitive, even to normal blood levels of these hormones. Surges in hormones e.g. during puberty, pregnancy or pre-menstrually can drive production of extra sebum.
  3. Medical conditions, such as polycystic ovarian syndrome (PCOS), increase the risk of persistent acne and may be tested for by your doctor if you have other symptoms, such as irregular menstrual cycles, thinning of scalp hair and excess body or facial hair. PCOS has been estimated to affect approximately 8% of females of reproductive age.
  4. Population studies correlate acne with a Western diet. Eating lots of sugary or processed foods and drinks may increase breakouts. Dairy can be a trigger for some people too. Unfortunately, there is no simple test to confirm or exclude this, so the best way to work it out is to observe closely over a few weeks (e.g. 6-8 weeks) to see if you can spot a pattern. Does your acne flare up consistently each time you consume dairy during this period? If so, does it get better when you limit dairy for the same amount of time?
  5. Other lifestyle factors can also contribute. Stress, certain medications (e.g. oral steroids, progesterone-only contraception, some antidepressant or antiepileptic drugs) and inappropriate skincare product or makeup selection can aggravate acne.

What does acne look like?

Generally straightforward to recognise, acne can appear in different forms:

  • Whiteheads (closed plugged pores)
  • Blackheads (open plugged pores)
  • Papules (small red bumps)
  • Pustules (small pus-filled spots)
  • Nodules and cysts (large, deep, tender lumps under the skin)

Many people who experience acne have a combination of these different types.

Acne is most likely to affect the face, however,  the trunk (back or chest) is affected in approximately 60% of cases. Adult female acne often affects the sides of the cheeks, jawline, chin, neck and upper torso. Teenage acne may be more prominent across the forehead, nose and chin, in the so-called T-zone distribution. In reality, there is usually some degree of overlap between these patterns.

It is important to understand that acne can leave scars or discolouration on the skin, some of which might remain long after the acne has subsided.

Common examples of these changes include:

  • Dark marks (post-inflammatory hyperpigmentation or “PIH”) 
  • Red marks (post-inflammatory erythema or “PIE”)
  • Hypertrophic or keloid scars (raised, thick or lumpy scars)
  • Atrophic scars e.g. rolling, box car or ice pick scars (pitted or indented scars) 

What is “fungal acne”?

Pityrosporum folliculitis is a yeast infection of the hair follicle and sebaceous gland. It is distinct from acne although some of the risk factors are similar e.g. high sebum production. Excessive sweating and hot, humid conditions can increase the risk too. It is most common in adolescent and young adult males, and typically affects the upper back and chest, although the forehead/ hairline, neck and chin can be affected too. 

Pityrosporum folliculitis causes small, red pimples which may be itchy. These are very uniform in appearance, unlike acne where a mixture of blackheads and other types of pimple often appear together. 

It is treated with antifungal shampoos, creams or tablets. Recurrence is common, even after successful treatment.

How is acne classified?

There are numerous grading systems used to define acne severity, but broadly speaking Dermatologists classify acne as mild, moderate or severe based on the number and type of spots, and the amount of skin involved. 

Factors which indicate more severe acne include:

  1. Large number of spots
  2. Presence of nodules and cysts
  3. Presence of scarring
  4. Presence of psychological distress

Acne and mental health

Acne is a very visible condition, it often persists for months or years and it can leave permanent scars. Anxiety, depression and low self-esteem are common in people who have had acne, and it has been repeatedly demonstrated that the level of distress may not correlate directly with acne severity i.e. people with objectively mild acne may experience significant distress.

Effective treatment of acne can relieve feelings of shame or embarrassment, and improve body image and self-confidence.

How should I manage my acne?

“The basics”

First and foremost, keep your skincare routine simple and stick to it as much as possible. 

One common acne myth is that poor hygiene causes acne. The role of facial cleansing in acne is to remove makeup, dirt and excess oil. Using harsh cleansers and scrubbing furiously at the skin can disrupt the skin barrier, increase inflammation and cause the skin to sting or burn.

Cleansing twice-daily with a gentle soap-free cleanser tends to work best. Then, opt for a non-comedogenic moisturiser, sunscreen and makeup. Non-comedogenic makeup improves confidence and does not worsen the severity of acne nor delay response to treatment.


Magazines and social media abound with skincare products that claim to improve or reduce breakouts. Although largely untested in controlled clinical trials, many of these products are considered somewhat effective, particularly for people with mild acne i.e. blackheads, and occasional papules or pustules. 

Adding products to your routine that contain benzoyl peroxide, salicylic acid, azelaic acid, alpha hydroxy acids, sulphur or niacinamide may help reduce oiliness, promote exfoliation and calm redness associated with acne. You don’t need to try and incorporate ALL of these ingredients, however. Doing so is likely to cause significant irritation.

Another nifty option in the over-the-counter toolbox, especially for those who are prone to picking spots, is the hydrocolloid plaster. 

If you are already following a sound skincare routine, have tried a few over-the-counter products without success or have any of the features that indicate more severe acne, prescription therapy is likely to be required and should not be delayed in people who are starting to scar.


Prescription creams (e.g. retinoids), the combined oral contraceptive pill, a trial of antibiotics or more specialised oral treatment options can be extremely effective when used in the right combination for you. 

The best doctors to see for acne treatment are your GP in the first instance, and a Consultant Dermatologist if initial treatment is not helping.

Light and laser treatments 

These treatments show some promise in treating acne and may form part of a treatment plan. Data confirming their effectiveness is limited compared to prescription treatment and more studies are needed to know what will work best for most people. 


The first step in managing acne scarring is to get the spots under control as early as possible. Once the acne is controlled, discolouration and texture does tend to improve to a degree over the following months. Broad-spectrum SPF 30 -50 sunscreen is an essential tool for helping fade dark or red marks from acne.

There are various tools and techniques that can be used to improve the appearance of scars. Topical retinoids, microneedling, radiofrequency needling, laser, chemical peels, steroid injections and surgical scar revision are all possible options. These treatments carry their own risk of adverse effects so need to be carefully tailored to the individual by an experienced practitioner on a case by case basis.

Managing Expectations 

People having treatment for acne should be given reasonable expectations of the time taken for visible improvement, which is usually 2-3 months for most options. It is important to understand that acne may worsen or irritation may be more significant initially, with gradual improvement. Be patient, be open-minded and don’t lose heart. There is always something that can be done.