Hormonal effect on psoriasis in pregnancy and post partum.

OBJECTIVES To investigate prospectively how psoriasis fluctuates in pregnancy and post partum and to correlate hormone levels in pregnancy (progesterone and estrogens) with psoriatic change. DESIGN Psoriatic body surface area (BSA) in pregnant patients with psoriasis (study group) and nonpregnant, menstruating patients with psoriasis (control group) were assessed 5 times over a year. Hormone levels (progesterone and estrogens) were measured in the study group and correlated with change in BSA. SETTING University-affiliated obstetric and dermatology clinics. PATIENTS Forty-seven pregnant patients in the psoriasis group and 27 nonpregnant, menstruating patients in the control group. RESULTS During pregnancy, 55% of the patients reported improvement, 21% reported no change, and 23% reported worsening. However, post partum, only 9% of patients reported improvement, 26% reported no change, and 65% reported worsening. Psoriatic BSA decreased significantly from 10 to 20 weeks' gestation (P<.001) compared with controls, whereas BSA increased significantly by 6 weeks post partum (P = .001) compared with controls. In patients with 10% or greater psoriatic BSA who reported improvement (n = 16; mean BSA, 40%), lesions decreased by 83.8% during pregnancy. There were significant or near significant correlations between improvement in BSA and estradiol (P = .009, r = 0.648), estriol (P = .06, r = 0.491), and the ratio of estrogen to progesterone (P = .006, r = 0.671). CONCLUSION High levels of estrogen correlated with improvement in psoriasis, whereas progesterone levels did not correlate with psoriatic change.