The blocked sebum-filled hair follicle promotes overgrowth of the bacterium Cutibacterium acnes (formerly called Propionibacterium acnes), which is normally present in the hair follicle. [merckmanuals.com]

• Pain

  However, if the acne is consistently large and painful, or has produced scars, treatment by a physician may be necessary. [merckmanuals.com]

• Inflammation

  The resulting inflammation causes the skin bumps that are commonly known as acne pimples. Deeper inflammation causes cysts and sometimes an abscess. [merckmanuals.com]

• Diarrhea

  Drugs Used to Treat Acne Drug Some Side Effects Comments Kills bacteria (applied to the skin) Clindamycin Diarrhea (rarely) Should be avoided in people with inflammatory bowel disease Dapsone Temporary skin yellowing when used with another product that [merckmanuals.com]

• Hypertension

  […] continuing while they take it and for 1 month after they stop taking it Requires blood tests to check whether the drug is affecting blood cells, the liver, or fat levels Blocks action of hormones (taken by mouth) Contraceptives High blood pressure (hypertension [merckmanuals.com]

• Dry Eyes

  eyes, chapped lips, and drying of the mucous membranes Pain or stiffness of large joints and lower back with high dosages Associated with depression, suicidal thoughts, attempted suicide, and (rarely) completed suicide, but whether isotretinoin is the [merckmanuals.com]

• Dry Skin

  skin, redness Foam propellant is flammable. [merckmanuals.com]

• Ulcer

  […] dosages Associated with depression, suicidal thoughts, attempted suicide, and (rarely) completed suicide, but whether isotretinoin is the actual cause is unknown Unclear whether associated with new or worsened inflammatory bowel disease (Crohn disease and ulcerative [merckmanuals.com]

• Skin Disease

  Acne is the most common skin disease in the United States and affects 80% of the population at some point in life. [merckmanuals.com]

• Skin Discoloration

  discoloration Most effective antibiotic according to some experts but is expensive Erythromycin Stomach upset Frequently, development of bacterial resistance to erythromycin Azithromycin Stomach upset Fewer side effects than erythromycin Frequently, [merckmanuals.com]

• Vaginal Bleeding

  bleeding (for example, between menstrual periods) Weight gain Stomach upset Headaches For treatment of acne in females Spironolactone Light-headedness Increased urination Breast tenderness Stomach upset For treatment of acne in females Doctors sometimes [merckmanuals.com]

• Vertigo

  […] bacterial resistance to erythromycin Azithromycin Stomach upset Fewer side effects than erythromycin Frequently, development of bacterial resistance to azithromycin Sarecycline Sensitization of skin to sunlight Stomach upset Light-headedness,dizziness, or vertigo [merckmanuals.com]

• Dizziness

  […] safe, but must be taken on an empty stomach Requires use of protective clothing and sunscreen during sun exposure Doxycycline Sensitization of skin to sunlight Requires use of protective clothing and sunscreen during sun exposure Minocycline Headache Dizziness [merckmanuals.com]

• Headache

  […] affecting blood cells, the liver, or fat levels Blocks action of hormones (taken by mouth) Contraceptives High blood pressure (hypertension), blood clots, breakthrough vaginal bleeding (for example, between menstrual periods) Weight gain Stomach upset Headaches [merckmanuals.com]

• Irritability

  […] skin Well-tolerated Frequent development of bacterial resistance Minocycline Irritation, dry skin, redness Foam propellant is flammable. [merckmanuals.com]

Acne treatment depends on the severity of the condition. Mild acne requires the simplest treatment that poses the fewest risks of side effects. More severe acne or acne that does not respond to preliminary treatment requires additional treatment. [merckmanuals.com]