Acne is caused mainly because of hormonal changes. The sebaceous glands react to these changes by releasing excess sebum. This blocks hair follicles. When dirt, dead skin cells and oil mix, it causes painful inflammations below the blockages that erupt over the surface of the skin. Bacteria often attack these blockages causing swelling, pain and pus to be formed. Acne manifests as blackheads, whiteheads, pustules or nodules.
Treatment is required to clear acne quickly. When simpler over-the-counter treatment like topical creams or lotions does not work, we require stronger topical antibiotics or oral antibiotics. Antibiotics for acne are prescription medications that can be given only by a certified doctor. They are often used as part of a combined treatment for severe acne.
Topical Antibiotics
Topical antibiotics for acne are part of the first line of therapy to combat acne. They destroy bacteria that cause infection in blocked hair follicles. These are available as gels or lotions and must be applied 1-2 times daily for 6-8 weeks at least. Treatment using topical antibiotics must be stopped after this period since bacteria can become resistant to them with prolonged use. This could in fact worsen acne outbreaks.
Topical antibiotics include clindamycin and erythromycin. They reduce inflammation, kill bacteria, and are used for treating mild to moderate outbreaks. Combinations of benzoyl peroxide and topical antibiotics like erythromycin and clindamycin work very well in treating inflammatory acne.
Side effects with topical antibiotics include minor skin irritation, peeling, burning and redness of the skin.
Oral Antibiotics
Oral antibiotics for acne are usually given in combination with topical medications to combat severe acne. They reduce the population of P.acnes bacteria and decrease inflammation. All dosages of oral antibiotics start with high dosages and this keeps reducing as the acne symptoms decreases. When P.acnes becomes resistant to a particular antibiotic, doctors will recommend another antibiotic or even another course of treatment.
Tetracycline : This is prescribed for most acne cases unless you are pregnant or breastfeeding. It is taken for a minimum of 6 weeks before you see any improvement in the acne. Depending on the severity of acne, it may need to be taken for 4-6 months. Tetracycline reduces the size of inflammatory lesions. It is usually recommended for those with papules – tiny tender, pink pimples – and pustules that have a red base with a white or yellow center.
Tetracycline causes side effects like skin sensitivity. It also makes oral contraceptives ineffective. Hence, those who are practicing contraception may need to shift to some other form during their treatment. In pregnant or breastfeeding women the use of tetracycline can affect the bones and teeth of babies causing skeletal and growth defects. In young children it can cause stained teeth also
When plain tetracycline is not very effective in treating acne, any one of its derivatives (doxycycline or minocycline) is prescribed.
Doxycycline: This is a tetracycline derivative and is effective against inflammatory acne. . Doxycycline is available as capsules, liquids or tablets. It must be taken with food to prevent upset stomach. Doctors usually start with a dose of 50-100mg of doxycycline. It causes sun sensitivity in some people. Some patients experience heartburn or sore throat if doxycycline is taken without food.
Minocycline: This is another tetracycline derivative and is used where other antibiotics have failed. There have been fewer reports of 
P.acnes becoming resistant to minocycline as against other antibiotics. It must be taken with water. Those who get upset stomach can take it with a glass of milk.
Erythromycin: This is also a popular antibiotic for acne. It is used both as oral and topical medication. It is safe for even pregnant and breastfeeding women. It is effective in combating broad spectrum bacteria that includes P.acnes.
Side effects of erythromycin are gastric problems, skin irritation and redness.
Clindamycin: This antibiotic is used widely to treat acne. It is semi-synthetic and prescribed more as a topical antibiotic than oral tablets. It is safe and tolerated by most people. Side effects include irritation and dryness of the skin.
Sodium Sulfacetamide: This fights infection and helps to unclog pores. It is used to treat severe, painful and inflammatory acne. Some people do not like this due to its strong odor of sulfur and gritty texture. However, newer formulations have taken care of these problems.
Side Effects of antibiotics for acne
One main side effect of antibiotics that can be dangerous is an allergic reaction. Symptoms of allergy to antibiotics include itchiness, hives, swelling of the face, tongue and mouth and difficulty in breathing. Seek medical attention at the nearest hospital if you experience any of these symptoms. Severe allergies can cause serious complications and lead to death.
Antibiotics taken over a long period may cause resistance to not only P.acnes, but to other bacteria as well. To protect the patient, doctors may taper off antibiotics for acne as soon as symptoms show an improvement or when the drugs do not seem to work.
Digestive problems like stomach cramps, diarrhea, and loss of appetite, nausea and vomiting are all severe side effects you can experience with antibiotics.
Other general side effects of all the above antibiotics include skin discoloration and dizziness. Antibiotics increase sensitivity to the sun and reduce the effect of oral contraceptives. Patients can also experience hearing loss, muscle weakness, yellowing of skin and eyes, blistered skin and irregular heartbeat.
Precautions when taking antibiotics
Antibiotics are not recommended for children below the age of 9, pregnant and breastfeeding women. It is very important to inform your doctor if you are pregnant as certain antibiotics can cause birth defects. Doctors will prescribe a safer line of treatment for them. Women who are on antibiotics for acne for several months could be susceptible to yeast infections. Tetracycline can be passed to babies through breast milk and cause a host of growth and developmental problems.
All antibiotics must be taken only under medical supervision and any side effects reported immediately.