A double-blind study of 21 patients taking 50 mg of hydrochlorothiazide twice daily for ten days beginning seven days before the menstrual cycle and a placebo in an effort to control premenstrual acne failed to demonstrate any usefulness of the diuretic in this condition. There was no demonstrable relationship between edema and premenstrual acne flare-up nor alleviation of the acne when edema was reduced.
Jelinek JE. Hydrochlorothiazide and the Control of Premenstrual Exacerbation of Acne. Arch Dermatol. 1972;105(1):79-80. doi:10.1001/archderm.1972.01620040051010