Case with pyoderma gangrenosum abruptly emerging around the wound of cesarean section for placenta previa with placenta accrete.

A 39-year-old woman underwent emergency cesarean section (CS) due to placenta previa totalis with massive bleeding. Two major problems emerged in this patient after CS was carried out. One was partial retention of the placenta due to placenta accreta. Another major and more serious problem was pyoderma gangrenosum (PG) widely appearing at the skin of the abdomen around the CS wound. Conservative treatment was performed for the retained placenta, and it had completely disappeared by 76 days after the CS. The diagnosis of PG was promptly made in consultation with a plastic surgeon and a dermatologist when a wide ulcer emerged around the CS wound, and high-dose prednisolone was administered as treatment. At 90 days following the CS, near-complete epithelialization was achieved. This extremely rare case reflects the importance of rapid diagnosis and treatment of PG.

Case of allergic contact dermatitis due to 1,3-butylene glycol.

1,3-Butylene glycol (1,3-BG) is widely used in cosmetics, including low-irritant skin care products and topical medicaments, as an excellent and low-irritation humectant. We report a case of allergic contact dermatitis caused by 1,3-BG. A 28-year-old woman suffered from an itchy erythematous eruption on her face. By 2 days of closed patch testing, her own cosmetics and many of the hypo-irritant skin care products showed positive results. A second patch testing showed positive reaction to 1,3-BG (1% and 5%). 1,3-BG was a common component in most of the products that had elicited a positive reaction in the first patch testing. Although allergic contact dermatitis due to 1,3-BG is not so common, we have to consider 1,3-BG as a possible contact allergen in the patients presenting with allergic contact dermatitis due to various cosmetics.

Mutation analysis of the IL36RN gene in 14 Japanese patients with generalized pustular psoriasis.

Generalized pustular psoriasis (GPP) is a rare, potentially life threatening, and aggressive form of psoriasis, which is characterized by sudden onset with repeated episodic skin inflammation leading to pustule formation. Familial GPP is known to be caused by recessively inherited mutations in the IL36RN gene, which encodes interleukin 36 receptor antagonist (IL-36Ra). In this article, we performed mutation analysis of the IL36RN gene in 14 Japanese patients with GPP, and identified mutations in two of these patients analyzed. One patient was compound heterozygous for mutations c.115+6T>C and c.368C>G (p.Thr123Arg), whereas the other carried compound heterozygous mutations c.28C>T (p.Arg10*) and c.115+6T>C in the IL36RN gene. Expression studies using total RNA from the patients' skin revealed that the mutation c.115+6T>C resulted in skipping of exon 3, leading to a frameshift and a premature termination codon (p.Arg10Argfs*1). The protein structure analysis suggested that the missense mutation p.Thr123Arg caused misfolding and instability of IL-36Ra protein. In vitro studies in cultured cells showed impaired expression of the p.Thr123Arg mutant IL-36Ra protein, which failed to antagonize the IL-36 signaling pathway. Our data further underscore the critical role of IL36RN in pathogenesis of GPP.