Pyoderma gangrenosum associated with pseudo-Pelger-Huet anomaly in a patient with idiopathic myelofibrosis.

Pseudo-Pelger-Huët anomaly is a condition in which almost all the granulocytes are hyposegmented and/or hypogranulated. It is typically recognized in peripheral blood smears and represents a marker of several disorders, such as myeloproliferative diseases and myelodysplasia. The occurrence of the pseudo-Pelger-Huët anomaly in the cutaneous infiltrate of pyoderma gangrenosum is very rare. We describe the case of a 70-year-old man with idiopathic myelofibrosis who developed pyoderma gangrenosum. Histological examination showed an infiltrate consisting of granulocytic elements with features of dysmaturity and segmentation anomalies (hypo- and hypersegmented forms), suggestive of pseudo-Pelger-Huët anomaly. Methylprednisolone treatment resulted in progressive improvement of pyoderma gangrenosum.

Association between short-term exposure to environmental air pollution and atopic dermatitis flare in patients treated with dupilumab.

Background: The magnitude of short/medium-term air pollution exposure on atopic dermatitis (AD) flare has not been fully investigated. The aim of the study was to investigate the association of short/medium-term exposure to airborne pollution on AD flares in patients treated with dupilumab. Methods: Observational case-crossover study. Patients with moderate-to-severe AD under treatment with dupilumab were included. The exposure of interest was the mean concentrations of coarse and fine particulate matter (PM10, PM2.5), nitrogen dioxide, and oxides (NO2, NOx). Different intervals were considered at 1 to 60 days before the AD flare and control visit, defined as the visit with the highest Eczema Area and Severity Index scores >8 and ≤7, respectively. A conditional logistic regression analysis adjusted for systemic treatments was employed to estimate the incremental odds (%) of flare every 10 µg/m3 pollutant concentration. Results: Data on 169 of 528 patients with AD having 1130 follow-up visits and 5840 air pollutant concentration measurements were retrieved. The mean age was 41.4 ± 20.3 years; 94 (55%) men. The incremental odds curve indicated a significant positive trend of AD flare for all pollutants in all time windows. At 60 days, every 10 µg/m3 PM10, PM2.5, NOx, and NO2 increase concentration was associated with 82%, 67%, 28%, and 113% odds of flare, respectively. Conclusions: In patients treated with dupilumab, acute air pollution exposure is associated with an increased risk for AD flare with a dose-response relationship.