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.