Impetigo herpetiformis with IL36RN mutations in a Chinese patient: A founder haplotype of c.115+6T>C in East Asia

Deficiency of interleukin-36 receptor antagonist (DITRA): An analysis of 58 Chinese patients in a tertiary hospital in Taiwan

DITRA, acronym for deficiency of interleukin-36 receptor antagonist (IL36RN), leads to unopposed pro-inflammatory signalling which typically manifests as pustular psoriasis. In Asian patients, c.115 + 6 T > C mutation is the most common and important single-nucleotide variant in DITRA. We present the largest case series consisting of 58 DITRA patients carrying heterozygous or homozygous c.115 + 6 T > C mutation. The mean age of onset (±SD) was 20.74 (±20.86), and the median age of onset was 13 years old. Twelve patients (20.7%) had disease onset before the age of two. Twenty-two patients (37.9%) had disease onset between the ages of 2-18. Main clinical phenotype was generalized pustular psoriasis (GPP) with systemic symptoms (33 patients, 56.9%), followed by acrodermatitis continua of Hallopeau (ACH) (16 patients, 27.6%). Nearly half of our patients (27 patients, 46.6%) ever had ACH, and only three of them are free of ACH currently, which indicates that the development of ACH is relatively persistent and irreversible. Thirty-four patients (58.6%) had recurrent GPP and 29 patients (50%) have been admitted due to GPP flare. Compared to those with heterozygous (C/T) mutation, more patients carrying homozygous mutation (C/C) have recurrent episodes of GPP (C/T vs. C/C: 25.53 vs. 76.47%, p = 0.0367). Two patients with squamous cell carcinomas arising from the pustular psoriasis skin lesions were noted. Two patients had elevated serum IgG4 levels.

Impetigo herpetiformis: A rare pregnancy-specific dermatosis

Impetigo herpetiformis (IH) is a pregnancy-specific dermatosis that is currently considered a form of generalised pustular psoriasis and mainly occurs in late pregnancy during the third trimester. IH presents as erythematous patches and pustules and might have systemic involvement. The disease may be associated with severe maternal, fetal, and neonatal complications. IH treatment is very challenging, however, various therapeutic options are available and effective for disease treatment.

Neutrophil Extracellular Traps in Skin Diseases

Neutrophils are the primary innate immune cells, and serve as sentinels for invading pathogens. To this end, neutrophils exert their effector functions via phagocytosis, degranulation, reactive oxygen species generation, and neutrophil extracellular trap (NET) release. Pathogens and pathogen-derived components trigger NET formation, leading to the clearance of pathogens. However, NET formation is also induced by non-related pathogen proteins, such as cytokines and immune complexes. In this regard, NET formation can be induced under both non-sterile and sterile conditions. NETs are enriched by components with potent cytotoxic and inflammatory properties, thereby occasionally damaging tissues and cells and dysregulating immune homeostasis. Research has uncovered the involvement of NETs in the pathogenesis of several connective tissue diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and ANCA-associated vasculitis. In dermatology, several skin diseases clinically develop local or systemic sterile pustules and abscesses. The involvement of neutrophils and subsequent NET formation has recently been elucidated in these skin diseases. Therefore, this review highlights the NETs in these neutrophil-associated diseases.

Papulosquamous Disorders and Pregnancy

Pregnancy can influence the course of a number of dermatologic disorders. Interestingly, these disorders can also influence pregnancy outcomes negatively, due to a variety of underlying pathogenic mechanisms. These outcomes may range from low fetal birth weight, preterm birth, and miscarriages to perineal lacerations complicating deliveries. Our review highlights the impact that papulosquamous disorders may have on pregnancy and their course throughout pregnancy. We chose papulosquamous disorders due to their relatively high prevalence worldwide compared to other dermatologic disorders. This review also sheds light on any gaps in the literature relevant to this topic that should be addressed. 

An update on genetic basis of generalized pustular psoriasis (Review)

Generalized pustular psoriasis (GPP) is a rare and severe auto-inflammatory skin disease that is characterized by recurrent, acute onset, and generalized pustular eruptions on erythematous, inflamed skin. GPP is traditionally classified as a variant of psoriasis vulgaris, even though recent clinical, histological and genetic evidence suggests that it is a heterogeneous disease and requires a separate diagnosis. In recent years, variants of IL36RN, CARD14, AP1S3 and MPO genes have been identified as causative or contributing to genetic defects in a proportion of patients affected by GPP. These disease-related genes are involved in common inflammatory pathways, in particular in the IL-1/IL-36-chemokines-neutrophil pathogenic axis. At present, no standard therapeutic guidelines have been established for GPP management, and there is a profound need for novel efficacious treatments of GPP. Among them, biological agents antagonizing the IL-36 pathway are promising therapeutics. The aim of the present review is to provide the most recent updates on the genetics, genotype-phenotype correlation and pathological basis of GPP, as well as on biologic treatments available for GPP and relative clinical courses.

Significance of IL36RN mutation analyses in the management of impetigo herpetiformis: A case report and review of published cases

Impetigo herpetiformis (IH) is a rare variant of generalized pustular psoriasis (GPP), which develops during pregnancy. GPP is associated with mutations of IL36RN, but it is still unclear whether the same is true of IH. A 20-year-old Japanese woman developed erythema and pustules on her trunk during the 27th week of her first pregnancy. Within 1 month, the skin lesions spread over her whole body, accompanied by fever. Skin biopsy revealed Kogoj's spongiform pustules in the epidermis and she was diagnosed with IH. Systemic administration of prednisolone failed to resolve the skin eruption, but it was partially improved by the addition of cyclosporin. The patient gave birth to a healthy female infant. After delivery, her erythema relapsed and the effect of granulocyte and monocyte adsorption apheresis was limited. Thus, secukinumab was administrated, and since then, she has maintained complete remission. Mutation analysis revealed a homozygous c.28C>T (p.Arg10X) mutation in IL36RN. Twelve cases of IH, including that presented here, have been reported together with the results of IL36RN genetic analyses, and 10 of the 12 cases occurred in East Asia (Japan and China) despite the fact that IL36RN mutations in GPP have been reported worldwide. Among 10 IH patients of East Asian descent, seven had IL36RN mutations, all of which were founder mutations causing GPP in East Asia: c.28C>T (p.Arg10X) or c.115+6T>C (p.Arg10ArgfsX1). Thus, East Asian founder mutations may play an important role in the pathogenesis of IH. IH patients with IL36RN mutations have a tendency to require biologics to resolve postpartum flare-ups or sustained psoriatic skin lesions. Because IL36RN mutation status may help predict postpartum flare-ups in IH patients, mutation analysis should be considered to enable preparation for biologic therapy of intractable flare-ups.

Efficacy and safety of treatment with anti-tumor necrosis factor-α drugs for severe impetigo herpetiformis

Impetigo herpetiformis (IH) is a rare pustular dermatosis. It can be life-threatening for both the mother and fetus and often causes therapeutic problems. However, there is no specific guideline for the treatment of IH and the evidence regarding the efficacy of treatments for IH has not been established. Herein, we report two cases of IH, which were successfully treated with anti-tumor necrosis factor (TNF)-α drugs. The serum levels of the drugs in the infants and mothers were examined using enzyme-linked immunosorbent assay (ELISA). Case 1 was a 35-year-old, gravida 2, para 1, female patient in week 20 of pregnancy; she was treated with adalimumab (ADA) until delivery. Case 2 was a 26-year-old, gravida 1, para 0, female patient in week 30 of pregnancy; she was treated with certolizumab pegol (CZP) until delivery. In both cases, the skin lesions started regressing considerably after administration of the biologic agents. We examined the serum levels of the biologic agents in the mothers and infants using ELISA. In case 1, the ADA serum level in the infant was as high as that in the mother at birth; it then decreased below the lower limit of quantification at week 12 post-delivery. In case 2, the CZP serum level in the infant was below the lower limit of quantification at birth. In this report, we revealed that biologic agents could be an effective treatment for severe IH and that CZP treatment can be considered safe for the mothers and fetuses.

Impetigo Herpetiformis: Review of Pathogenesis, Complication, and Treatment

Impetigo herpetiformis (IH) is among rare dermatosis of pregnancy, which is currently considered as a form of generalized pustular psoriasis. It is diagnosed by characteristic lesions of erythematous patches and grouped pustules mostly in the third trimester of pregnancy and may have systemic associations. A variety of complications have been reported in the course of IH. Treatment of IH can be quite challenging, and a number of treatment options have been reported to be effective for the management.

Pustular psoriasis of pregnancy: current perspectives

Pustular psoriasis of pregnancy (PPP) is a life-threatening condition for both the pregnant mother and fetus, and must be efficiently and accurately diagnosed and treated. This condition has historically been classified as a unique, separate dermatosis of pregnancy. However, current opinion and data suggest that it may be a variant of generalized pustular psoriasis. PPP typically occurs in the third trimester and is characterized by widespread coalescent pustules, desquamation, and systemic symptoms. Clinical features and histopathologic evaluation aid in diagnosis. Treatments during pregnancy include high-dose corticosteroids, cyclosporine, narrow-band ultraviolet B radiation, infliximab, granulocyte and monocyte adsorptive apheresis, and systemic antibiotics. Both the mother and fetus should be closely monitored with appropriate laboratory studies for the duration of the pregnancy and postpartum.

European consensus statement on phenotypes of pustular psoriasis

Pustular psoriasis (PP) is a group of inflammatory skin conditions characterized by infiltration of neutrophil granulocytes in the epidermis to such an extent that clinically visible sterile pustules develop. Because of clinical co-incidence, PP is currently grouped with psoriasis vulgaris (PV). However, PP and PV are phenotypically different, respond differently to treatments and seem to be distinct on the genetic level. In contrast to PV, the phenotypes of PP are not well defined. Descriptions of each form of PP are discordant among standard dermatology textbooks [Saurat Dermatologie 2016, Rook's Dermatology 2016, Fitzpatrick's 2012 and Braun-Falco 2012], encumbering the collection of phenotypically well-matched groups of patients as well as clinical trials. The European Rare and Severe Psoriasis Expert Network (ERASPEN) was founded to define consensus criteria for diagnosis, deeply phenotype large groups of PP patients, analyse the genetics and pathophysiology and prepare for prospective clinical trials. This work reviews historical aspects of these conditions, new genetic findings and presents our initial considerations on the phenotypes of PP and a consensus classification of clinical phenotypes that will be used as a baseline for further, prospective studies of PP. Generalized pustular psoriasis (GPP) is defined as primary, sterile, macroscopically visible pustules on non-acral skin (excluding cases where pustulation is restricted to psoriatic plaques). GPP can occur with or without systemic inflammation, with or without PV and can either be a relapsing (>1 episode) or persistent (>3 months) condition. Acrodermatitis continua of Hallopeau (ACH) is characterized by primary, persistent (>3 months), sterile, macroscopically visible pustules affecting the nail apparatus. Palmoplantar pustulosis (PPP) has primary, persistent (>3 months), sterile, macroscopically visible pustules on palms and/or soles and can occur with or without PV.