'Fade out' photochromonychia

Area of Science:

• Dermatology
• Cosmetic Science

Background:

• Hydroquinone is a common ingredient in over-the-counter depigmenting creams.
• Nail pigmentation changes are not a widely recognized side effect of topical hydroquinone use.

Observation:

• Two women using topical hydroquinone developed chestnut-brown nail pigmentation.
• Pigmentation intensified with increased sun exposure.
• Discoloration resolved after discontinuing hydroquinone or protecting nails from it.

Findings:

• Topical hydroquinone can cause characteristic nail staining.
• Sunlight exposure significantly influences the intensity of hydroquinone-induced nail pigmentation.
• Nail pigmentation is reversible upon cessation of exposure to the causative agent.

Implications:

• Clinicians should be aware of potential nail staining from hydroquinone.
• Patients using hydroquinone should be advised about sun protection for their nails.
• This highlights the importance of considering environmental factors like light exposure in adverse drug reactions.