Conventional Medical Treatment
There are a variety of treatment options available for acne. Medications may target one or more of the several underlying causes of acne, such as excessive androgen signalling, overproduction of sebum, bacterial overgrowth, and inflammation (Archer 2012; Dawson 2013; Garner 2012; Simonart 2013; Agak 2013; Tan 2007; Zouboulis 2010; First Consult 2013).
Less severe acne is typically treated with topical preparations, some of which are attainable over-the-counter (OTC) without a prescription, whereas systemic, prescription-only medications may be utilized in addition to topical agents in severe cases. Also, systemic medication may occasionally be employed for less severe acne that has proven resistant to first-line topical agents (First Consult 2013; Garner 2012). For acne scarring, advanced cosmetic procedures such as laser resurfacing, dermabrasion, and chemical peels may be helpful (First Consult 2013; Rai 2013; Khunger 2008). Consulting with a dermatologist is advised since there are so many treatment options available for acne; an experienced physician can help each patient determine the approach that best suits their individual needs.
Over-The-Counter Topical Agents
The following topical agents are often considered “first-line” treatments. They are available in OTC formulations, but some stronger concentrations or preparations in which they are combined with other types of medication may be available by prescription only.
Benzoyl peroxide. Benzoyl peroxide is often used for mild to moderate cases of acne (Sagransky 2009). It is a bactericidal agent, which means it kills bacteria. It is normally prescribed in conjunction with topical antibiotics, but has been shown to be effective against acne when used alone (Kircik 2013; Costa 2013). A combination benzoyl peroxide and antibiotic therapy is typically sold in the form of gels containing up to 10% benzoyl peroxide and often 1% antibiotic (eg, clindamycin) (Baumann 2013; Fluhr 2010).
Azelaic acid. Azelaic acid is a naturally-occurring compound that has anti-inflammatory and antimicrobial properties (Reis 2013; Mastrofrancesco 2010). It is indicated for mild and moderate acne.
Salicylic acid. Salicylic acid is typically used for non-inflammatory acne. Applied as a 0.5 – 2% lotion, cream, or gel, it helps the outer layer of skin to soften and shed (ie, it is considered keratolytic). Salicylic acid can also be found in some OTC facial washes (First Consult 2013; ePocrates 2013).
Several antibiotics may be utilized for acne treatment. Both topical and oral formulations of antibiotics are available, with the latter being reserved for more severe cases.
Erythromycin. Erythromycin is an antibiotic that kills P. acnes and has anti-inflammatory activity (Melnik 2013). For treating acne, it is available as a topical formulation at a concentration of 2% typically (Faghihi 2012). It has been found to be most effective when combined with azelaic acid in topical formulations (Pazoki-Toroudi 2010).
Clindamycin. Clindamycin is an antibiotic typically prescribed in a topical formulation for mild to moderate cases of acne. In combination with benzoyl peroxide, it can reduce microorganism counts by just over 99% after one week of treatment (Kircik 2013).
Nadifloxacin. A 2013 study demonstrated that 76 strains of P. acnes had no resistance to nadifloxacin (Takigawa 2013). In one study, 1% nadifloxacin cream was observed to be as effective as 4% erythromycin gel (43 patients per antibiotic group over twelve weeks) in treating mild to moderate acne (Tunca 2010).
Metronidazole. Metronidazole is used as a topical solution for its antimicrobial and anti-inflammatory properties. Despite its history of use as a medication for moderate acne, there are few studies that have assessed its actual effectiveness in clearing lesions. In one study, there was a slightly greater chance of adverse skin effects caused by 2% metronidazole gel compared to placebo, but 88% of the patients were satisfied with the effects of the treatment (Khodaeiani 2012).
Trimethoprim-sulfamethoxazole. Trimethoprim-sulfamethoxazole is a combination of two separate antibiotics - trimethoprim and sulfamethoxazole - that is more effective than either antibiotic alone (McCarty 2011). It has been used extensively for moderate to severe acne; however, there is evidence that some P. acnes strains are resistant to this treatment (Schafer 2013). Like the other antibiotics prescribed for acne, it is often formulated with benzoyl peroxide or another complementary chemical treatment (McCarty 2011).
Tetracyclines. Tetracyclines are a group of oral antibiotics that were popular for the control of moderate to moderate-severe acne; however, they are becoming less popular for a number of reasons. Tetracyclines are associated with hyperpigmentation of skin that may be irreversible (Garner 2012). They are also often associated with adverse effects such as gastrointestinal disturbances, photosensitivity, headache, and tinnitus (Shalita 2012); and these drugs have a higher-than-average cost (Garner 2012).
Azithromycin. Azithromycin belongs to a group of antibiotics known as macrolides. They have been shown in clinical trials to be as effective as certain tetracyclines for treating acne (Maleszka 2011; Babaeinejad 2011). Azithromycin is often combined with isotretinoin (see next section) to treat moderate to severe acne; after approximately 21 weeks of treatment the combination achieved complete clearance of symptoms in over 90% of subjects in one trial (De 2011).
Tretinoin. Tretinoin (all-trans-retinoic-acid), a retinoid (vitamin A-related compound) usually marketed as a topical cream, has proven effective against mild to moderate acne (Baldwin 2013). It can regulate some aspects of immune response related to the inflammation seen in acne (Agak 2013). In a double-blind, randomized trial, 156 patients were given either a 0.04% or 0.1% tretinoin gel to apply nightly for 12 weeks. Both concentrations achieved significant reductions in total lesion count, though the 0.1% group showed a greater decrease in inflammatory lesions at two weeks (Berger 2007). Another multicenter open-label trial using patients who found their former acne treatments ineffective used these same concentrations and formulations. In this study, 183 patients were assigned to the 0.1% formulation and 361 to the 0.04% gel. Both concentrations produced significant improvements in observer rating scores and Global Acne Grade scores (Eichenfield 2008).
Tazarotene. Tazarotene is another retinoid chemically similar to tretinoin. It is available as a 0.05 - 0.1% foam, gel, or cream for moderate to severe acne (First Consult 2013). Like tretinoin, it normalizes immune response, helping to mitigate inflammation (Duvic 1997; Zheng 2008). Tazarotene, regarded as a teratogen (a compound known to cause fetal abnormalities), carries warning labels directed at women of childbearing age (Epstein 2013).
Adapalene. Adapalene (also a retinoid) is a popular and effective treatment for mild and severe acne. It has an efficacy about equal to that of benzoyl peroxide (Babaeinejad 2013). Adapalene has anti-inflammatory properties and disrupts comedones (Prasad 2012). It appears to act by inhibiting the product of sebum by sebocytes, thus suppressing sebum build-up (Sato 2013). It is available as a topical treatment by itself or in combination with benzoyl peroxide (Kim 2013) or an antibiotic (Prasad 2012).
Isotretinoin. Oral isotretinoin may be prescribed for severe acne after other treatments have failed (Mayo Clinic 2012). It is a form of all-trans-retinoic-acid (Melnik 2010). There is evidence of an association between isotretinoin administration and potentially severe depression (Bremner 2012). Isotretinoin has a variety of immunomodulatory effects; unfortunately, it is also a teratogen (Melnik 2010; Melnik 2011). Female patients of childbearing age are advised to consider fetal risks if a pregnancy occurs and must use two forms of birth control while on isotretinoin (Mayo Clinic 2012). Isotretinoin can also produce other adverse effects, most notably muscle weakness (Georgala 1999).
Spironolactone. Spironolactone is a diuretic drug that also disrupts androgen signalling. Due to its activity as an antiandrogen, it may help reduce sebum production in some acne patients (Kim, Del Rosso 2012). It is prescribed to women who are not pregnant and is not typically used in men due to the possibility of feminization (Rathnayake 2010).
Oral contraceptives. Oral contraceptive pills (OCPs) may be prescribed to women with moderate to severe acne. This type of contraceptive contains a progestin (a synthetic progesterone-like drug) alone or in combination with an estrogen. These counteract androgen signalling and thus treat acne caused by androgen excess (Arowojolu 2012). There are many types of OCPs. Some appear to be more effective in treating acne.
- A trial comparing 45 women taking 150 mcg desogestrel + 30 mcg ethinyl estradiol to 46 women taking 150 mcg levonorgestrel + 30 mcg ethinyl estradiol (an older OCP) showed that the decrease in acne was significantly higher in the first group (Sanam 2011).
- Norgestimate, at doses of 0.180 mg, 0.215 mg or 0.250 mg, each with 0.035 mg ethinyl estradiol, was shown to be significantly effective for moderate facial acne in two randomized, placebo-controlled trials in which 324 subjects received 6 treatment cycles (Tan 2007).
- Drospirenone is a spironolactone derivative that acts as a progestin. In two randomized, controlled trials on 889 women, 3 mg of drospirenone along with 0.020 mg ethinyl estradiol achieved total- or near-total clearance of acne scores in 18% of subjects compared to only 6% of subjects receiving a placebo (Tan 2007).
Dermabrasion. Dermabrasion, which involves removal of the top layers of skin with an abrasive material or tool to allow new, smoother skin to regrow, may be used to reduce the appearance of acne scars (Picosse 2012). Dermabrasion use is decreasing for acne scar treatment in favor of laser resurfacing, but is still a useful treatment option for mild areas of atrophic scarring (ie, scars that form a sunken recess in the skin) that are not likely to worsen (Levy 2012).
Laser therapy and laser resurfacing. Lasers are very high-intensity light sources. Lasers are produced by shining light through various elements and/or crystals such as erbium, garnet, and yttrium, which causes it to be focused into a concentrated beam of light. Certain lasers such as carbon dioxide (CO2) lasers have shown great efficacy in treating and improving the appearance of acne scars (Shah 2012). These lasers work by removing a thin layer of skin with minimal heat damage (First Consult 2013). Some lasers operate in treating acne by destroying the P. acnes bacteria and damaging the sebaceous glands, causing them to produce less oil (Rai 2013; Mayo Clinic 2011c). Fractional lasers, which are focused on specific affected areas rather than the traditional whole-face approach, are one of the most efficient modern laser therapies (Shah 2012). Laser resurfacing has a longer healing time and higher cost than dermabrasion (First Consult 2013).
Chemical peels. 'Chemical peeling' involves the application of relatively high concentrations of various types of chemicals (usually acids) to affected skin in order to remove the top layers of skin and potentially improve superficial scarring (Bae 2013; Takenaka 2012; Khunger 2011; First Consult 2013). Different strengths of chemical peels are available, ranging from mild to “deep.” Deep chemical peels are done with stronger concentrations of acids at targeted points on the skin.
Alpha hydroxy acids. Alpha hydroxy acids (AHAs) are often used in skin conditions; at high concentrations they act as chemical peels (Takenaka 2012). Examples of AHAs are lactic acid and glycolic acid (Kornhauser 2010). AHAs disrupt both comedone formation and the activity of P. acnes in the skin. A placebo-controlled trial of a 10% glycolic acid wash found that it was significantly effective in reducing mild acne and was well tolerated (Abels 2011). Lactic acid has been shown to give significantly positive results as a chemical peel (92% concentration) for mild acne scarring (Sachdeva 2010). A trial of gluconolactone, another AHA, at 14% concentration in a lotion, was compared to 5% benzoyl peroxide lotion in a double-blind trial of 150 subjects. Both were found to be equally effective in reducing the number of acne lesions (Hunt 1992).