Elevated cutaneous expression of stem cell factor in chronic spontaneous urticaria: a prospective cohort study.

BACKGROUND: Tissue expression of endothelial cell (EC) markers of microcirculatory changes in CSU is poorly investigated. OBJECTIVE: to explore the expression of specific EC markers (stem cell factor (SCF), vascular endothelial growth factor (VEGF) and membrane attack complex (MAC)) in CSU-L and CSU-NL skin through immunohistochemistry (IHC) and in serum. METHODS: Lesional (L) and non-lesional (NL) skin biopsies from CSU patients and HCs were studied for the IHC expression of SCF, VEGF and MAC in CSU patients (n = 23) and healthy controls (HCs, n = 9). In this population, we also investigated blood levels of VEGF and SCF. Patients were also assessed for clinical characteristics, disease activity, and markers of autoimmune CSU (aiCSU). RESULTS: Epidermal SCF reactivity was significantly higher in CSU-L skin compared to HC skin (p=0.026). In the dermis, SCF immunoreactivity was seen particularly on endothelial, perivascular and epithelial cells. In CSU-L skin, mean perivascular SCF stainings were significantly more intense compared to HCs (p<0.001). Furthermore, CSU-NL skin also showed significantly higher SCF stainings on dermal perivascular cells compared to HCs (p<0.001). CSU patients had the highest SCF immunoreactivity scores in the epidermis and/or on dermal ECs. These patients did not have significantly higher SCF serum levels. CONCLUSION: This is the first study to show elevated cutaneous expression of SCF in chronic spontaneous urticaria. These findings underline the potential therapeutic possibilities of anti-KIT antibodies in CSU treatment.

A clinicopathological description of COVID-19-induced chilblains (COVID-toes) correlated with a published literature review.

BACKGROUND: The abundance of publications of COVID-19-induced chilblains has resulted in a confusing situation. METHODS: This is a prospective single-institution study from 15 March to 13 May 2020. Thirty-two patients received PCR nasopharyngeal swabs. Of these, 28 patients had a thoracic CT-scan, 31 patients had blood and urine examinations, 24 patients had skin biopsies including immunohistochemical and direct immunofluorescence studies, and four patients had electron microscopy. RESULTS: COVID-19-induced chilblains are clinically and histopathologically identical to chilblains from other causes. Although intravascular thrombi are sometimes observed, no patient had a systemic coagulopathy or severe clinical course. The exhaustive clinical, radiological, and laboratory work-up in this study ruled-out other primary and secondary causes. Electron microscopy revealed rare, probable viral particles whose core and spikes measured from 120 to 133 nm within endothelium and eccrine glands in two cases. CONCLUSION: This study provides further clinicopathologic evidence of COVID-19-related chilblains. Negative PCR and antibody tests do not rule-out infection. Chilblains represent a good prognosis, occurring later in the disease course. No systemic coagulopathy was identified in any patient. Patients presenting with acral lesions should be isolated, and chilblains should be distinguished from thrombotic lesions (livedo racemosa, retiform purpura, or ischemic acral necrosis).

Associated pyoderma gangrenosum, erythema elevatum diutinum, and Sweet's syndrome: the concept of neutrophilic disease.

BACKGROUND: The association of three neutrophilic dermatoses supports the concept of "neutrophilic disease" as a syndrome representing a continuous spectrum of clinical entities. RESULTS: This report describes three neutrophilic pathologies arising in the same patient, in association with seronegative rheumatoid arthritis. The successive occurrence of erythema elevatum diutinum, pyoderma gangrenosum, and Sweet's syndrome illustrates the concept of "neutrophilic disease" developed by Wallach et al. in the 1990s. Most authors agree that neutrophilic dermatosis is defined as a cutaneous disease mainly characterized by polymorphonuclear neutrophil infiltration without infectious cause.The assessment of neutrophilic dermatosis includes identification of the type of cutaneous lesion, the existence of possible extracutaneous sites, and a search for associated disease. CONCLUSIONS: The occurrence of three separate neutrophilic dermatoses in a single patient lends further support to the concept that these entities form a spectrum of diseases called neutrophilic disease.