Topical and Oral Antibiotics for Acne: Best Ones, How Long to Take Them, and More

• Antibiotics can effectively kill acne-causing bacteria and reduce inflammation
• Topical antibiotics are typically prescribed for mild-to-moderate acne and oral antibiotics for severe acne
• Oral antibiotics are associated with more side effect than topical treatments
• Antibiotics should always be combined with other acne treatments to avoid bacterial resistance

Acne is an extremely common skin condition among both adolescents and adults. It can vary from mild to severe, and usually requires months and sometimes years of focused treatment, often with multiple medications. Since the role of bacteria in acne was discovered, antibiotics for acne have been an important component in its management. 

How Do Antibiotics Treat Acne? 

A bacterium called Cutibacterium acnes (formerly Propionibacterium acnes) plays a key role in the development of acne by releasing enzymes that break down surrounding oils and skin cells, and triggering inflammation.

Antibiotics are medications that target bacteria; some can directly kill bacteria and others work by preventing their growth and replication. In addition to fighting bacteria, many antibiotics have anti-inflammatory effects.

Should you use antibiotics for acne?

Antibiotics are effective against most types of inflammatory acne, such as inflamed pimples, pustules and mild cystic breakouts. However, they are not effective against hormone-related acne. 

Oral antibiotics are typically prescribed for moderate-to-severe forms of inflammatory acne. Topical antibiotics are used for milder cases that don’t respond to standard topical treatments.

Antibiotics are especially effective when combined with other acne oral medications or topical treatments with different mechanisms of action, including benzoyl peroxide, isotretinoin, spironolactone and oral contraceptives.

One drawback of using an antibiotic to treat acne is antibiotic resistance. Experts have known for some time that when an antibiotic is used for prolonged periods, the bacteria it targets can mutate to become immune to the effects of the antibiotic. This makes the bacteria more aggressive and harder to kill. 

Strategies to reduce the risk of bacterial resistance include:

• Using the antibiotic only as prescribed and for the shortest period of time
• Using antibiotics with low rates of resistance
• Combining oral antibiotics with a topical retinoid or benzoyl peroxide to increase efficacy

Topical Antibiotics for Acne

Since they are applied directly to the skin, topical antibiotics work by accumulating in follicles to target and destroy bacteria, and provide anti-inflammatory effects. 

Numerous topical antibiotics are available including creams, gels, lotions, solution, medicated wipes and foams. They are typically recommended for mild acne, but can also be effective for treating severe acne when combined with other acne treatments. 

Clindamycin and erythromycin are the most commonly used topical acne antibiotics. Other options include dapsone and sulfacetamide.

Clindamycin

Clindamycin works by preventing bacteria from multiplying and has anti-inflammatory properties.

Clindamycin is effective against mild-to-severe acne. It can reduce the severity and number of both inflammatory and noninflammatory acne lesions. When combined with other acne treatments such as benzoyl peroxide or retinoids, the improvements are even greater.

Clindamycin is available as a gel, foam, solution, lotion or medicated wipe. The oral form of clindamycin is not used in the treatment of acne as it can cause diarrhea and inflammation of the colon.

Dapsone

Dapsone is effective at treating noninflammatory acne lesions but is most effective against inflammatory acne. In two large-scale clinical trials, the number of inflammatory lesions in people treated with dapsone 5% gel were reduced by almost half (47.5%) after 12 weeks of treatment. 

In another study, when researchers looked at gender, the same treatment was most effective in women.

Erythromycin 

Erythromycin belongs to the macrolide class of antibiotics, which work through a mechanism similar to clindamycin by inhibiting bacterial growth.

Like clindamycin, erythromycin is recommended for mild, moderate or severe acne in combination with other acne medications. Erythromycin and clindamycin are similarly effective.

Erythromycin is available as a cream, gel, lotion or swab. Unlike clindamycin, oral erythromycin can be prescribed to treat acne.

Oral Antibiotics for Acne

Oral antibiotics work systemically. This means that instead of being applied directly to lesions, they are ingested and absorbed by the blood and carried to where bacteria have accumulated. 

Since the entire body is exposed to oral antibiotics, they’re more likely to cause side effects. For this reason, dermatologists reserve them for more severe forms of acne. 

Oral antibiotics should be combined with topical retinoids and benzoyl peroxide to increase effectiveness of the antibiotic and decrease the risk of bacterial resistance.

The oral antibiotics most often prescribed for acne treatment are macrolides and tetracyclines.

Macrolides

Macrolides stop bacterial replication by interfering with protein production. The macrolides erythromycin and azithromycin are as effective in treating inflammatory acne as doxycycline.

However, macrolides carry an increased risk of side effects and bacterial resistance. In addition they are unsafe for women who are pregnant or thinking of becoming pregnant. 

Tetracyclines

Like macrolides, tetracyclines prevent the growth of bacteria by inhibiting a protein that’s key to their replication. 

Tetracyclines can clear up lesions caused by moderate-to-severe inflammatory acne. This includes papules (pus-free pimples), pustules, nodules and cysts. 

Of the tetracyclines, doxycycline is the one dermatologists prescribe most often and is very effective in killing P. acnes bacteria.  

Sarecycline is a relatively new tetracycline that is FDA-approved and has shown significant improvements in addressing moderate-to-severe acne. This drug has also been associated with a low risk of side effects.

Trimethoprim-sulfamethoxazole

Trimethoprim-sulfamethoxazole (TMP-SMX) is a drug that is typically used to treat serious infections. It has been shown to be effective when used off-label for severe acne. However, it has potentially severe side effects such as bone marrow suppression and toxic epidermal necrolysis, a condition that resembles a severe burn in which skin can slough off.

TMP-SMX is limited to patients who are unable to take other acne medications and for whom other treatments have failed to clear up their acne. 

How Long Should You Take Antibiotics for Acne?  

While there is no hard limit on how long you can use antibiotics, their use should be limited to the shortest possible period to minimize the risk of developing bacterial resistance. Both topical and systemic antibiotics can cause resistance.

Antibiotics are typically prescribed for 3–4 months. Your dermatologist will then reevaluate whether you need to continue taking them. Some people with severe acne may need to use antibiotics for 6 months or longer.

It can take as little as 2 weeks after starting an antibiotic to see some improvements; for others it can take up to 12 weeks.

You should not stop or change the dosage of antibiotics without first consulting your dermatologist. Using antibiotics incorrectly can contribute to the development of bacterial resistance.

Side Effects

Side effects depend on which antibiotic you use and whether you take it orally or use it topically. Oral antibiotics are more commonly associated with side effects than topicals.

The side effects of tetracyclines include nausea, vomiting, diarrhea, rash, esophagitis (inflammation of the esophagus) and photosensitivity (increased susceptibility to ultraviolet rays that increases the risk of sunburn). 

They can also cause color changes in the skin and damage the bones and teeth of young children and infants when women use tetracyclines while pregnant.

Macrolides can cause nausea, vomiting, abdominal pain, hearing loss and electrocardiogram (ECG) changes.

Topical antibiotics can cause skin dryness, itching, redness and exfoliation. 

Tetracyclines should be avoided by pregnant women as they can harm unborn children and cause permanent staining of the baby’s teeth later in life.

Takeaway 

Antibiotics are the cornerstone of acne therapy. There are several oral and topical antibiotics proven to be effective in treating inflammatory and noninflammatory acne. Topicals are typically prescribed for mild forms of acne, oral treatments for moderate-to-severe cases.

It can take some trial and error to find the right medication or combination of medications that work for you. Your dermatologist may prescribe a topical retinoid or benzoyl peroxide to produce greater results. 

Because bacterial resistance is a concern with prolonged antibiotic use, they should be used for the shortest amount of time possible. It is also important to use your medication as directed.