Nobody had said how much

Marguerite Oyelowo was applying roughly a tenth of the intended quantity, faithfully, twice a day, for four years.

Quantity is the most under-explained part of topical treatment. Patients are given a tube and an instruction and left to invent the dose.

Fingertip units

The psychological load of a visible condition is asked about routinely at every appointment, because it does not correlate with severity and is otherwise never mentioned.

We hand over a tube and let people invent the dose. Then we call it treatment failure.

Dr. Ilse Marchand, dermatology

Beyond the rash

Flare plans are written down with thresholds, so treatment starts on day one of a flare rather than on day nine when it has become unbearable.

“It wasn’t that it didn’t work,” she says. “It’s that I’d never actually taken it.”