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).

Belgian National Survey on Tinea Capitis: Epidemiological Considerations and Highlight of Terbinafine-Resistant T. mentagrophytes with a Mutation on SQLE Gene.

BACKGROUND: In this last decade, a huge increase in African anthropophilic strains causing tinea capitis has been observed in Europe. The Belgian National Reference Center for Mycosis (NRC) conducted a surveillance study on tinea capitis in 2018 to learn the profile of circulating dermatophytes. METHODS: Belgian laboratories were invited to send all dermatophyte strains isolated from the scalp with epidemiological information. Strain identification was confirmed by ITS (Internal Transcribed Spacer) sequencing. Mutation in the squalene epoxidase (SQLE) gene was screened by PCR. RESULTS: The main population affected by tinea capitis was children from 5-9 years. Males were more affected than females. The majority of the strains were collected in the Brussels area followed by the Liege area. Among known ethnic origins, African people were more affected by tinea capitis than European people. The major aetiological agent was Microsporum audouinii, followed by Trichophyton soudanense. One strain of Trichophyton mentagrophytes has been characterized to have a mutation on the squalene epoxidase gene and to be resistant to terbinafine. CONCLUSIONS: African anthropophilic dermatophytes are mainly responsible for tinea capitis in Belgium. People of African origin are most affected by tinea capitis. The monitoring of terbinafine resistance among dermatophytes seems necessary as we have demonstrated the emergence of resistance in T. mentagrophytes.

Refractory Trichophyton rubrum infection in lamellar ichthyosis.

A 10-month-old boy with congenital lamellar ichthyosis presented with a chronic Trichophyton rubrum infection. There was no history of atopy or immunosuppression, and examination revealed high total immunoglobulin E (IgE) with a positive specific IgE for T. rubrum. Multiple treatments with fluconazole were necessary to control the infection. T. rubrum is present worldwide and is responsible for the vast majority of chronic dermatophytosis. Lamellar ichthyosis is a risk factor for chronic dermatophytosis because of excessive keratin and the barrier defect. A delayed-type hypersensitivity reaction to T. rubrum is associated with cure, whereas immediate hypersensitivity and IgE are not protective and may lead to chronic infection. Atopy and the Th2 profile therefore seem to be associated with chronic dermatophytosis. The association between ichthyosis and atopy is well documented. T. rubrum also has an interesting ability to evade immunity, which helps explain the chronic infection. Finally, in ichthyosis, it is likely that fluconazole has difficulty penetrating the acanthotic stratum corneum, which explains treatment failure. We report this case to alert clinicians to the possible association between lamellar ichthyosis and chronic dermatophytosis and to report the difficulties of management.