Exogenous Ochronosis (EO) (For Professionals)

• Causes: resorcinol, phenol and mercury.
• Risk factors: olive or dark skin, failure to use sunprotection.
• Occurs with prolonged use of hydroquinone (HQ) at a concentration of more than 3%.
• FDA banned OTC (Over-the-counter) sale due to toxicology issues and uncertain long term cancer risk. However, it is considered safe when used at a concentration of 2% or less under the supervision of a physician.

Contributors:

Dr Christophe HSU – dermatologist. Geneva, Switzerland

Source of Information: Alrawashdeh B. Melasma Update. Dubai World Dermatology & Laser Conference & Exhibition – Dubai Derma 13 – Dubai, United Arab Emirates (UAE)