Pustular psoriasis of pregnancy: Clinical and genetic characteristics in a series of eight patients and review of the literature

Pustular psoriasis of pregnancy (PPP) can lead to life‐threatening complications. The objective of this study is to report clinical and genetic spectrum, prognostic factors and management options. A retrospective study was designed including eight PPP patients. Clinical data were collected, and performed genetic and statistical analysis to identify factors associated with fetal complications, resistance to treatment and post‐partum flare extension. A systematic review of the literature was also carried out. Eight Tunisian patients, with a mean age of 23 ± 3.3 years, were included. They presented 14 flares (F) during pregnancies and one flare after delivery. Additional GPP flares outside pregnancy periods were noted in 2/8 of patients. The mean duration of PPP flares was 16.66 ± 7.8 weeks. The first flare occurred at a gestational age of 26 ± 5 weeks. Only 2/8 studied patients presented a homozygous mutation c.80 T > C (p.L27P) in IL36RN gene. Used treatments were topical steroids (n = 12F), systemic steroids (n = 5F), ciclosporin (n = 1F), UVB (n = 1F) and acitretin (in post‐partum n = 6F). Complications were oligoamnios (n = 2), intra‐uterine growth retardation (n = 1), fetal death in utero (n = 1), prematurity (n = 3), low weight at birth (n = 2). A significant association was found between (i) occurrence of fetal complications and early gestational age at the onset (p = 0.036), (ii) resistance to topical steroids and body surface affected area (p = 0.008), (iii) presence of mutation c.80 T > C in PPP flares and low serum levels of calcium (p = 0.01). Our systematic review of the literature identified 39 patients with 41 flares of PPP. Only 7/39 patients presented a causative mutation in IL36RN and CARD14 genes. PPP is characterized by a phenotypic heterogeneity and can be associated to IL36RN mutations. Its early onset can be associated with fetal complications. Systemic steroids and cyclosporine remain the most used therapies.