What is the recommended amount of topical cream or ointment (e.g. triamcinolone acetonide) to apply per skin surface area?

Guidelines for Topical Cream and Ointment Application Amounts

The fingertip unit (FTU) is the standard measurement for determining the amount of topical cream or ointment needed per body area, where 1 FTU equals approximately 0.5 grams and covers approximately 2% body surface area (two adult palm-sized areas). 1

Fingertip Unit Method

The FTU is defined as the amount of ointment or cream expressed from a tube with a 5mm diameter nozzle, applied from the distal skin crease to the tip of the palmar aspect of the index finger. 2

Recommended FTU Amounts by Body Area

For single application:

• Face and neck: 2.5 FTU (~1.25 grams) 1
• One hand (front and back): 1 FTU (~0.5 grams) 1
• One entire arm including hand: 4 FTU (~2 grams) 1
• One entire leg including foot: 8 FTU (~4 grams) 1
• Trunk (anterior or posterior): 8 FTU each (~4 grams each) 1
• Scalp: 3 FTU (~1.5 grams) 1
• Genitalia: 0.5 FTU (~0.25 grams) 1
• Buttocks: 4 FTU (~2 grams) 1

Alternative Measurement: Grams per Body Surface Area

For liberal application (when complete coverage is desired), use 40-50 grams per square meter per application. 3

• Cream formulations: 40 g/m² per application 3
• Ointment formulations: 50 g/m² per application 3

This translates to approximately 100 grams per week to treat 10% body surface area when applying twice daily. 3

Two-Week Supply Calculations

For emollients and maintenance therapy, the following amounts are recommended per 2 weeks for single daily application: 1

• Face and neck: 15-30 grams 1
• Both hands: 15-30 grams 1
• Scalp: 15-30 grams 1
• Groins and genitalia: 15-30 grams 1
• Both arms: 30-60 grams 1
• Both legs: 100 grams 1
• Trunk: 100 grams 1

Critical Application Considerations

Ointment vs. Cream Spreading

Ointments spread more evenly than creams or solutions and deliver more consistent dosing across the treated area. 4 Creams and solutions have rapid evaporation of water/alcohol content, resulting in uneven distribution with lower doses at the periphery of application. 4 When using creams or solutions, instruct patients to apply to multiple sites and spread quickly to minimize evaporation-related uneven distribution. 4

Common Pitfalls to Avoid

Patients typically underdose topical medications. 3 In one study, patients used only 39 g/m² of cream (versus the recommended 40 g/m²) and this underdosing contributed to treatment failure. 3 When calculating prescriptions, account for the actual involved body surface area using the "Rule of Hand" (patient's palm including fingers = approximately 1% body surface area). 2

For potent topical corticosteroids used in extensive disease (such as bullous pemphigoid), specific dosing is: 1

• Maintenance therapy: 10 grams once weekly applied to previously affected areas 1
• Active disease control: 10-30 grams daily depending on extent (10g for localized, 20g for mild, 30g for extensive disease) 1

Maximum Safe Dosing Limits

For specific medications with toxicity concerns, observe maximum surface area limits: 1

• 5-Fluorouracil 5%: Maximum 500 cm² treatment area 1
• Ingenol mebutate: One tube per 25 cm² (single dose) 1
• Imiquimod 5%: One 250mg sachet per application area with 1cm margin 1