What is Acne?

Acne is a common skin condition, especially in adolescents and young adults. It is highly prevalent, in that approximately 50 million people in the US have acne. This condition can occur in most ages and can occur even in adulthood. Acne occurs when hair follicles become clogged with oil and dead skin cells, and then those clogged pores present as whiteheads, blackheads, or pimples. Acne is notable for its effect on the face and surrounding skin areas, as scarring and inflammation may occur.

Clinical Presentation of Acne

Acne commonly presents in the form of comedones (whiteheads and blackheads) and pimples. Comedones become clogged with oil, dead skin cells, and bacteria. Acne commonly appears on the face, forehead, chest, upper back and shoulders.

  • Whiteheads: closed comedone (skin pore or hair follicle)
    • Small bumps that appear white
  • Blackheads: open comedone (skin pore or hair follicle)
    • Small bumps that appear black
  • Papules: small red tender bumps
  • Pustules: also known as pimples; papules with pus at the tips
  • Nodules: large, solid, painful lumps under the skin
  • Cysts: painful, pus filled lumps under the skin

Causes/Risk Factors of Acne

Acne typically is caused by:

  • Excess oil/sebum production
  • Inflammation
  • Bacteria, such as Propionibacterium acnes
  • Hair follicles clogged by oil and dead skin cells

The specific presentation of acne occurs because those skin areas have the most oil or sebaceous glands, and those oil glands are connected to the hair follicles.

Other causes or triggers include:

  • Hormones: Hormones, such as androgens, are increased during the onset of puberty. Androgens cause sebaceous glands to become bigger and to produce more sebum, promoting the formation of acne. In women, changes in hormones during menopause may also trigger acne breakouts.
  • Medications: Certain medications, such as corticosteroids, lithium, and testosterone, can promote acne. Certain hormonal contraceptives may also alter hormone levels, causing increased acne.
  • Diet: Certain people may have acne that is triggered by food. Foods high in carbohydrates and fats are common triggers for acne.
  • Stress: Stress can worsen or increase acne already present.

Common risk factors for acne include:

  • Age: Acne is highly prevalent in teenagers.
  • Hormones: Acne can be triggered during puberty, pregnancy, and menopause; these periods consist of many hormonal changes.
  • Family history: Some people might have a genetic component to developing acne
  • Greasy or oily substances: Some people may get acne when using oily lotions and creams
  • Friction/pressure on skin: Some people might develop acne due to helmets, tight collars, cellphones, backpacks, etc.

Treatments for Acne

Acne can be controlled with over the counter products or with prescription medications. Treatments will depend on the age of the patient, involved sites, severity of disease, and overall patient preference. Treatments begin with topical medications, usually as monotherapy, or in combination with other topical agents, or in combination with oral agents.

The first line topical agents that are commonly used are:

  • Benzoyl Peroxide: Benzoyl peroxide is an antibacterial agent that kills the acne causing bacteria Propionibacterium acnes. It kills the bacteria by releasing free oxygen radicals that are toxic to the bacteria. Benzoyl peroxide also stops the formation of comedones, or the clogged pores/follicles. This medication can be used by itself or is commonly added to other medications to enhance the effectiveness of treatment. Results can be seen as early as 5 days.
    • Formulations: 2.5 to 10%; topical washes, foams, creams, gels
    • Directions: Applied once daily, can be increased to 2-3 times daily
    • Side Effects: dryness, redness, irritation
    • Availability: over the counter
  • Retinoids: Retinoids are vitamin A derivatives that inhibit the formation of comedones. They are also anti-inflammatory and help reduce acne lesions. Retinoids enhance any treatment regimen and are useful in maintaining clear skin after stopping oral agents.
    • Formulations:
      • Tretinoin: 0.025 to 0.1%; cream, gel, microsphere gel
      • Adapalene: 0.1%, 0.3% cream, 0.1% lotion
      • Tazarotene: 0.05%, 0.1%; cream, gel, or foam
    • Directions: Applied once daily, typically in the evening
    • Side effects: dryness, peeling, redness, irritation
    • Availability: prescription only
  • Antibiotics: Antibiotics, such as Clindamycin and Erythromycin, work by killing bacteria present in the follicles. They also provide anti-inflammatory effects. These medications should be used with benzoyl peroxide to reduce bacteria resistance and to increase antibiotic efficacy. Clindamycin is found to be more effective than erythromycin.
    • Formulations:
      • Clindamycin: 1%; solution or gel
      • Erythromycin: 2%; cream, gel, lotion, pledget
    • Directions: Applied once daily, typically in the morning
    • Side effects: redness, itching, dryness
    • Availability: prescription only
  • Azelaic Acid: Azelaic acid is a mild agent that inhibits formation of the comedone, kills bacteria and reduces inflammation. It is a naturally occuring acid produced by a yeast.
    • Formulations: 20%; cream or gel
    • Directions: Apply 2 times a day
    • Side effects: skin redness, irritation
    • Availability: over the counter (lower concentrations) and prescription (20%)
  • Salicylic Acid: Salicylic acid is commonly available in many over the counter products. It works by inhibiting formation of clogged pores. Overall, this is well tolerated.
    • Formulations: 0.5 to 2%; cream, gel, solutions, lotion, ointment, pad
    • Directions: Apply 2-3 times a day, as directed per formulation
    • Side effects: skin peeling, stinging
    • Availability: over the counter
  • Dapsone: Dapsone is a sulfone agent used for acne. It works by reducing inflammatory lesions. It is typically used more in women.
    • Formulations: 5%, gel
    • Directions: Apply 2 times a day
    • Side effects: redness, dryness
    • Availability: prescription only
  • Niacinamide: Niacinamide or vitamin B3 has been shown to provide anti-inflammatory activity, which would reduce acne related inflammation. It also helps build healthy skin cells and protect them from UV damage.
    • Formulations: topical, 10%
    • Side effects: redness, allergic reaction
    • Availability: over the counter
  • Tranexamic Acid: Topical tranexamic acid has been shown to have skin brightening activity, which helps improve discoloration due to acne.
    • Side effects: dryness
    • Availability: over the counter
  • Metronidazole: Metronidazole is a topical antibiotic. It is found to have anti-inflammatory and antimicrobial properties, which provides benefits for acne related inflammation. However, the bacteria that causes acne is found to be metronidazole resistant at commonly available concentrations of 0.75% and 1%, but not at 2%. Specially compounded metronidazole 2% may provide additional benefit for acne.
    • Side effects: burning, itching, dryness
    • Availability: prescription only
  • Ketotifen: Ketotifen is a histamine blocker and mast cell stabilizer. It has a possible role in reducing inflammation and itching that could occur due to acne. It may also reduce lesions caused by acne. This medication would have to be specially compounded in a topical form.
    • Availability: prescription only

Oral medications that are commonly used are:

  • Antibiotics: Oral antibiotics are commonly used for moderate to severe acne. They work by reducing and/or killing bacteria. These should be used for the shortest time possible in order to reduce the chance of antibiotic resistance. Benzoyl peroxide should be used with oral antibiotics to increase efficacy. The most commonly used antibiotic is Doxycycline. Azithromycin may be used for those who cannot take doxycycline ( children under age 8, pregnant women, allergy)
    • Directions:
      • Doxycycline 100 to 200mg once daily
      • Azithromycin 500mg daily for 2-5 days, repeated every month
    • Side effects:
      • Doxycycline & Azithromycin: photosensitivity, upset stomach
    • Availability: prescription only
  • Combination Oral Contraceptives: Oral contraceptives that consist of an estrogen and progestin are used to treat acne. They work as antiandrogens, decreasing androgen production and binding free testosterone to reduce its effect. It may take a few months before effects are visible. Currently, only 4 combinations are approved for treatment of acne (Ethinyl estradiol/norgestimate, Ethinyl estradiol/norethindrone/ferrous fumarate, Ethinyl estradiol/drospirenone, Ethinyl estradiol/drospirenone/levomefolate)
    • Directions: Take 1 tablet daily, as directed by your doctor
    • Side effects: increased risk of cardiac events
    • Availability: prescription only
  • Spironolactone: Spironolactone is an aldosterone receptor blocker and has potent antiandogen activity. It works by decreasing testosterone production and by stopping testosterone binding to receptors on the skin. This medication is considered for women if oral antibiotics are not effective.
    • Directions: 25 to 200mg daily
    • Side effects: breast tenderness, menstrual irregularities
    • Availability: prescription only
  • Isotretinoin: Isotretinoin is a vitamin A derivative. It is only used for patients who have not responded to other treatments for moderate and severe acne. It works by reducing sebum production, acne lesions, and acne scarring. Patients must participate in a FDA risk management program as this medication has potential to cause serious side effects, such as birth defects and depression. Patients will also be required to have regular doctor visits for side effect monitoring.


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