How come hydroquinone causes hyperpigmentation but is also supposed to get rid of hyperpigmentation?

Question

Hydroquinone is often prescribed by doctors as a bleaching agent, why is it that it also causes what it is supposed to treat????

Answer 1

It depends on the concentration of hydroquinone used. People w/ darker skin using it @ higher concentrations may end up w/ dark spots due to irritation.

I have a medium-dark complexion & sometimes I experience dark spots as my skin heals from a pimple or an allergic reaction. My dermatologist told me that the skin generates more cells to heal the affected area but it may also pump out more melanin in response.

"hydroquinone. Substance that is known to successfully reduce the intensity of freckles, melasma, and general brown patching by inhibiting melanin production. For continued and increased effectiveness it must be used long term. Unprotected sun exposure should be avoided, because it reverses the effect of hydroquinone by increasing melanin production. Occasionally, at higher concentrations, persons with a darker skin type will experience increased pigmentation, but this is rare. It can cause mild skin irritation and there is the possibility of an allergic reaction. Hydroquinone in 1% to 2% concentrations is available in over-the-counter products; 4% concentrations are available by prescription only (Source: American Journal of Clinical Dermatology, September-October 2000, pages 261�268)."
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