How to counsel and advise application

• Apply only to the residual normally pigmented skin, not to the already white vitiligo patches.
• On the face, use a very thin film, rubbed gently into the defined pigmented areas.
• A standard regimen is twice daily. The FDA label allows 2 to 3 times daily, but for facial skin many dermatologists begin cautiously, for example once daily for a short period, then increase to twice daily only if tolerated.
• Do not apply near the eyes, eyelid margins, lips, nostrils, or other mucosal surfaces. Wash hands well after application. Do not occlude the area.
• Review after about 4 to 6 weeks for irritation and response. Visible depigmentation often takes months. Textbook guidance describes twice-daily use for 3 to 6 months, occasionally up to 10 months. Andrews’ Diseases of the Skin, p. 1003.
• Once the desired uniform depigmentation is achieved, stop routine application and monitor for residual/re-pigmenting islands.

Essential informed-consent points

1. Permanent effect: Monobenzone kills melanocytes. Repigmentation may be difficult or impossible. It is intended for extensive vitiligo, generally when more than 50% BSA is involved. Goodman & Gilman’s The Pharmacological Basis of Therapeutics p. 2663.
2. It may spread beyond treated skin: satellite or distant, irregular depigmentation can occur, including on normal skin not directly treated. This is especially important if only a few facial areas remain pigmented. Andrews’ Diseases of the Skin, p. 1003.
3. Irritant or allergic dermatitis: redness, burning, itch, scaling, swelling, or blistering can occur. Stop it and contact the treating dermatologist if these develop. Around one in six patients may develop acute dermatitis in textbook series. Andrews’ Diseases of the Skin, p. 1003.
4. Strict photoprotection: avoid prolonged sun exposure; use broad-spectrum SPF 50+ sunscreen, hat, and physical protection. Depigmented skin burns easily. The Benoquin FDA label specifically advises avoiding prolonged sun exposure or using sunscreen.
5. Psychological and social implications: facial depigmentation changes appearance permanently. Discuss expectations, camouflage options, family support, and consider psychological assessment before starting. Andrews’ Diseases of the Skin, p. 1003.

Practical prescription-style instruction

Monobenzone 20% cream: Apply a very thin layer to the remaining normally pigmented facial skin only, avoiding eyes, eyelids, lips, nostrils, and white vitiligo patches. Start as directed by dermatologist and generally progress to twice daily if tolerated. Wash hands after use. Stop and report burning, marked redness, itch, swelling, blistering, or eczema. Use strict daily sun protection.