Melanin pigment production by melanocytes is a normal skin process that helps determine the unique color of your skin and hair. However, sometimes that process can go awry and produce excess melanin, triggered by a number of factors. These causes include:1
- ultraviolet rays from sun exposure
- injury or surgery
- heredity (i.e., freckles)
Other common dark spots on skin are so-called liver or age spots. Medically-termed solar lentigines, these yellow to dark-brown pigmented areas range in size from less than half of an inch to over an inch. They typically occur in lighter-skinned Caucasians or Asians after repeated or severe unprotected sun exposure, especially in people with a tendency to freckle. If you experience pain, itching, or bleeding in any of these areas it is imperative that you see a dermatologist to rule out skin cancer.2
Although hyperpigmentation skin disorders are usually physically benign, they can cause psychological distress—especially if they occur on parts of the body not typically covered by clothing (like the face and forearms).2
Hydroquinone’s skin bleaching ability mainly works by inhibiting the activity of tyrosinase, the enzyme necessary to convert the protein tyrosine to melanin. It also exhibits some toxicity towards melanocytes, caused by inhibition of cellular DNA and RNA (although this is reversible), and affects other proteins.3
Topical hydroquinone has been used with some success for over 30 years, but lightening effects can take months and may not last without continued use. Depending on the type and cause of pigment skin disorder, hydroquinone may be combined with other substances to produce the best result.2
- American Osteopathic College of Dermatology. Hyperpigmentation. Dermatologic Disease Database. [Online] 2010. http://www.aocd.org/skin/dermatologic_diseases/hyperpigmentation.html.
- Plensdorf, Scott and Martinez, Joy. American Family Physician Volume 79, Issue 2: Common Pigmentation Disorders. MD Consult: American Academy of Family Physicians. [Online] January 2009. http://www.mdconsult.com/das/article/body/178618016-2/jorg=journal&source=MI&sp=21650863&sid=0/N/680808/1.html?issn=0002-838X.
- Kanthraj, Garehatty Rudrappa. Skin-lightening agents: New chemical and plant extracts -ongoing search for the holy grail! Indian Journal of Dermatology, Venereology, and Leprology. [Online] 2010. http://www.ijdvl.com/article.asp?issn=0378-6323;year=2010;volume=76;issue=1;spage=3;epage=6;aulast=Kanthraj#ref2. DOI 10.4103/0378-6323.58671.