Psoriasis tip: How to apply medicine | AAD

Psoriasis tip: How to apply medicine

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Do you use a psoriasis medicine to treat your skin? If so, the instructions likely tell you how many milligrams of medicine to apply. This can make it difficult to know how much to use.

To help patients figure out how much medicine to apply, dermatologists developed an easy-to-use approach called the “fingertip unit.” All you need to use this approach is your medicine and a clean fingertip. A fingertip unit equals the amount of medicine that you can spread on your fingertip, as shown in the photo below.

 

Each part of the body requires a specific number of fingertip units. For example, if you have psoriasis on most of your scalp, you need to apply three fingertip units of medicine to your scalp. If psoriasis covers most of your elbow, you’d apply one fingertip unit.

The next time you need to apply psoriasis medicine to your skin, be sure to look at the following table. It shows you how many fingertip units to apply to each part of the body where you have psoriasis.

 Area to be treated
No. of fingertip units
 Scalp  3
 Face and neck
 2.5
 One hand (front and back) including fingers
 1
 One entire arm including entire hand
 4
 Elbow (psoriasis covers most of elbow)
 1
 Both soles
 1.5
 One foot (top and bottom) including toes
 1.5
 One entire leg including entire foot
 8
 Buttocks  4
 Knees (psoriasis covers most of knee)
 1
 Trunk (from bottom of neck to hipbones)
 8
 Genitals  0.5

Different parts of the body require a different number of fingertip units.

Chart reproduced from the Psoriasis Guidelines of Care developed by the American Academy of Dermatology. (Menter A, Korman NJ, et al. “Guidelines of care for the management of psoriasis and psoriatic arthritis.” J Am Acad Dermatol 2009;60:643-59.)

References:

Menter A, Korman NJ, et al. “Guidelines of care for the management of psoriasis and psoriatic arthritis.” J Am Acad Dermatol 2009;60:643-59.