Acne is a common chronic skin condition that occurs when hair follicles (pilosebaceous unit) become clogged with oil and dead skin cells, leading to the formation of microcomedones (small “clogged pores” with no opening), blackheads, whiteheads, and other types of lesions. It can occur on any part of the body, but is most commonly seen on the face, chest, and back. The medical term for acne is “acne vulgaris”. Acne is more than just a physical illness because it can cause substantial psychological and social issues for the patient especially if acne scars develop on the skin. Therefore, early intervention and treatment is important to not only treat acne, but to also prevent scarring as much as possible. (See below image)

Acne can be caused by a variety of factors, including:

• Genetics: Acne tends to run in families, so if your parents or siblings have had acne, you may be more likely to develop it.
• Hormonal imbalances: Hormonal changes during puberty, menstrual cycles, pregnancy, and menopause can all contribute to the development of acne.
• Increased oil (sebum) production
• Increased production of skin cells (hyperkeratinization)
• Bacteria: Cutibacterium acnes (C. acnes) is a type of bacteria that is normally found on the skin but can cause acne when it colonizes the follicle. [note: (Propionibacterium acnes was renamed to Cutibacterium acnes in 2016]
• Inflammatory reaction
• Oily skin
• Fungus/Yeast (pitysporum folliculitis): can be associated with seborrheic dermatitis (on scalp – “dandruff”)
• Lifestyle factors: diet (dairy, whey protein, sugar), stress (can affect hormones), tight fitting clothing, hygiene, hair washing/drying habits, picking at lesions, make-up, skin care products and certain medications can all contribute to the development of acne.
• Environmental factors: air pollution, temperature, humidity, grease contact (kitchen)

Types of lesions:

1. Non-inflammatory
   1. Microcomedones: commonly not visible to the naked eye, it is the precursor to other acne lesions. There is commonly microscopic excess oil and dead skin cells blocking the follicle.
   2. Comedones (“clogged pore”): small, raised bumps on the skin which can be “open” or “closed” depending on whether the follicle opening is covered or not by skin.
      • Closed comedone (“whitehead”): Small, raised bumps on the skin that are caused by trapped oil and dead skin cells. Underlying sebum or pus can be “whitish” in color partially seen through the skin. (See below image)
        
      • Open comedone (“blackhead”): a type of open comedone that are clogged with oil and dead skin cells, which turn black when they come into contact with air (oxidation).
2. Inflammatory
   1. Papules: Small, red bumps that are raised above the surface of the skin. (See below image)
      
   2. Pustules: Similar to papules, but with a white or yellow center that is filled with pus. Commonly with inflammation (redness, pain, swelling) around the lesion. (See below image)
      
   3. Nodules: Larger, more severe lesions that develop deeper within the skin. They are firm, painful, and can be deeply embedded. Nodules are often accompanied by inflammation and may take longer to heal compared to other types of acne lesions. (See below image)
      
   4. Cysts: Similar to nodules in size and depth but are filled with pus and can be softer to the touch. Cysts are often larger than other acne lesions and can be quite painful. (See below image)
      

Primary assessment of patients with acne starts with a proper history taking. Due to the multifactorial nature of acne, family history, environmental factors, diet, hygiene, make-up/skin care products, stress, physical activity, and medication history need to be evaluated. Close examination of the skin for comedones which can develop into more severe types of acne lesions is required in addition to the assessment of other larger acne lesion types and locations on the face/body.

Examination of the scalp is also needed to rule out any fungus/yeast component that may contribute to acne.

Effective treatment for acne depends on the severity and type of acne, as well as the individual patient’s skin type and medical history. As acne can also affect children and teenagers, age-specific safety of certain treatments must also be taken into consideration.

1. Modification of triggering factors: Environmental, lifestyle related factors (listed above)
2. Topical treatments: Help to prevent and reduce non-inflammatory lesions (comedones). Also important in the maintenance stage after treatment goals have been reached. Include: appropriate cleanser, AHA, BHA, benzol peroxide, azelaic acid, adapalene, retinoids (tretinoin). Topical antibiotics are used to treat mild to moderate inflammatory acne. However, improper use can lead to resistance so should be used in combination with other regimens and according to instruction by the physician. Include: clindamycin, erythromycin.
3. Oral treatments: Not the “first-line” of therapy unless for severe inflammatory acne with nodules.
   1. Oral antibiotics including doxycycline, minocycline, tetracycline and erythromycin can be effective for treatment of moderate to severe acne.
   2. Oral isotretinoin: US FDA approved for treatment of severe recalcitrant acne. Also, can be used for less severe acne that is treatment resistant. This medication is a potent teratogen (agent which causes malformation of an embryo) and can have other serious side effects. Regular negative pregnancy tests and laboratory blood test monitoring during therapy is required.
   3. Oral contraceptives: generally considered second-line therapies but may be considered first-line in women with adult-onset acne or perimenstrual flare-ups.
   4. Hormone therapy: Includes spironolactone. Effectiveness in acne is still unclear but can be used as second- or third-line agent or in women who cannot take isotretinoin. It is a diuretic (increases urine production) drug which is also a potential teratogen. Potential side effects include menstrual irregularities, breast tenderness and high potassium levels.
4. Laser and light therapies: LED, IPL, Pulsed-dye laser, photodynamic, photopneumatic devices
5. Other: comedone removal (extraction), steroid injections into nodular lesions, chemical peels

Acne is a very complex, chronic condition which is challenging to treat and can have long-term effects not only on the skin, but also mentally and socially. Cooperation between the patient and the treatment team is important in achieving treatment goals. After these goals are met, maintenance to prevent recurrence of acne is vital. Once acne maintenance is achieved, acne scar treatment can be taken into consideration.