Fingertip units is a term coined by CC Long and AY Finlay who, in an article published in 1991 , described a convenient way to measure how much cream to prescribe to a patient with skin disease. Accurate prescription is particularly important for topical steroids.
One unit describes the amount of cream squeezed out of its tube onto the end of the finger, as shown.
The quantity of cream in a fingertip unit varies with age:
- Adult male: 1 fingertip unit provides 0.5 g
- Adult female: 1 fingertip unit provides 0.4 g
- Child aged 4 years – approximately 1/3 of adult amount
- Infant 6 months to 1 year – approximately 1/4 of adult amount
The amount of cream that should be used varies with the body part:
- One hand: apply 1 fingertip unit
- One arm: apply 3 fingertip units
- One foot: apply 2 fingertip units
- One leg: apply 6 fingertip units
- Face and neck: apply 2.5 fingertip units
- Trunk, front and back: 14 fingertip units
- Entire body: about 40 units
An adult female applies a cream once daily to both arms. She uses 2.4 g in one day (2 arms x 3 fingertip units x 0.4 g = 2.4 g). This is 16.8 g per week (7 x 2.4 g).
A 30 g tube should last her two weeks. But if she applies it twice daily (4.8 g/day), the tube will be finished in less than a week (33.6 g/week).
An adult male applies a cream once daily to both feet and both hands. He uses about 3 g per day (2 feet x 2 units PLUS 2 hands x 1 unit, x 0.5 g = 3.0 g). This works out as 21 g/week (7 x 3 g).
A 50 g tube should last him about 2 1/2 weeks.
A baby has a cream applied twice daily to the entire body, i.e. about 10 g daily.