Hydroquinone is the gold-standard topical for treating multiple forms of hyperpigmentation. It is effective for hormonally induced dark patches like melasma, sun exposure related dark spots, and post-inflammatory hyperpigmentation due to acne, contact dermatitis, eczema and trauma. It can even correct freckles that patients are born with, called ephelides, and those that acquired with sun exposure, known as lentigines.
Hydroquinone inhibits the skin's protective response to UV exposure by inhibiting an enzyme called tyrosinase, thereby decreasing melanin production. In doing so it reduces spotty hyperpigmentation. When prescription strength HQ is combined with tretinoin, maximum results are achieved.
When using hydroquinone, some patients experience mild darkening of the treated spots around weeks 3-4. This is normal and will resolve as the pigment is expelled naturally through normal skin turnover.
Note: if used at high concentrations for an extended period of time, hydroquinone can cause paradoxical darkening, so it’s very important to follow your dermatologist’s instructions carefully. It is also important to diligently use sun protection when using hydroquinone; this avoids sensitivity and additional hyperpigmentation from developing.