Hydroquinone is a medication that is generally applied to the skin to help bleach areas of brown discoloration. Depending on the country a person lives in, he or she may have access to both prescription and non-prescription versions. No matter what the prescription status, however, hydroquinone can have some side effects and health-care providers typically recommend against its use in certain people.
Melanin is the brown pigment found in skin. Certain things, such as pregnancy and sun exposure, can cause melanin to be overproduced, leading to freckles, sun spots or large areas of discoloration. While not harmful to a person’s health, some people may find this skin darkening to be cosmetically unappealing and seek medical help. Hydroquinone is one of the medications health-care providers may prescribe for overpigmentation because it typically reduces the amount of melanin in the skin, helping bleach out dark spots that may have formed.
In the U.S., hydroquinone is typically available as both a prescription and non-prescription topical medication. The prescription versions contain higher amounts of the active ingredient, often up to 4 percent hydroquinone. Dermatologists and other skin care experts generally agree these stronger prescription versions help bleach skin more quickly. Over-the-counter versions are required by law to contain 2 percent or less of the active ingredient, and therefore often take longer to work. In some other areas, such as countries in the European union, all strengths of the medication require a prescription.
Regardless of the strength, hydroquinone can have some side effects. Common side effects that are generally considered mild may include temporary redness, itching or burning of the skin where the medication is applied. In rare cases, hydroquinone may actually cause further darkening of the skin where it is applied. This may be more likely to happen in people with naturally darker skin tones and those who don’t use sunscreen properly on the treatment areas. An allergic reaction, such as hives, swelling and trouble breathing, may also result in some cases.
Health-care providers generally warn against the use of hydroquinone in certain people. These typically include people with liver or kidney disease and women who are pregnant or planning to become pregnant. For people with liver and kidney disease, some studies have shown that hydroquinone may cause a worsening of the underlying condition. Other studies have shown that the medication may cause birth defects in developing animal fetuses, which is why it is generally contraindicated during pregnancy.