Onychomycosis.

Onychomycosis is a fungal infection of the nail, and the most common nail infection worldwide, causing discoloration and thickening of the nail plate. It is predominantly caused by dermatophytes. Clinical presentation is polymorphous. Diagnosis must be confirmed by mycological examination before initiating any therapy. Management is an ongoing challenge, often requiring several months' treatment, with a high risk of recurrence. Treatment must be adapted to clinical presentation and severity and to the patient's history and wishes. Debridement of all infected keratin is the first step, reducing fungal load. Systemic treatments are more effective than topical treatments, and combining the two increases the cure rate. Terbinafine is the drug of choice for dermatophyte onychomycosis, due to low drug interaction and good cost-effectiveness. Itraconazole and fluconazole are broad-spectrum antifungals that are effective against dermatophytes, yeasts, and some non-dermatophytic molds. Recurrence rates for onychomycosis are high. Prophylactic application of topicals and avoiding walking barefoot in public places may help prevent recurence.

Management of ingrowing nail.

For decades, there has been debate about the cause of ingrown nail: is the nail plate or the periungual tissue at fault? There is no consensus and management relies on case-by-case analysis followed by tailored treatment. Conservative treatment should be attempted in children when the cause is transient (e.g., poor clipping) or the patient refuses surgery. Surgical treatments rely on two main approaches: either narrowing the nail plate, or debulking the soft tissue. It is up to the surgeon to select the most appropriate approach in each case. All procedures discussed in this chapter have high cure rates as long as they are properly performed. As with all surgical procedures, they are operator-dependent. Chemical cautery is the easiest and most versatile technique that may help in almost all instances for lateral ingrowth. For distal ingrowth and very hypertrophic and exuberant lateral folds, debulking with primary or secondary healing is most effective.

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).

Nail is Systemic Disorders: Main Signs and Clues.

Describing and listing all nail symptoms and signs in systemic disorders has already been widely detailed in dedicated textbooks. To be tutorial, this article described most common nails signs and the systemic disorders one may encounter in routine dermatologic consultation. Capsule summaries are presented for each section.

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.

Nail Unit Blue Nevi: A 11-Case Series and Review of the Literature.

BACKGROUND: Blue nevus of the nail apparatus is a rare entity and only isolated cases are reported in the literature. OBJECTIVE: The aim of this study was to better characterize blue nevus at the nail unit. METHODS: Retrospective analysis of all nail unit blue nevi from the Nail Group of the French Society of Dermatology was compared to the literature. RESULTS: Eleven cases were retrieved from 2002 to 2019 with an average age of 45 years. The majority were women (9/11) and acquired (10/11). Hands were more frequently involved (9/11) with a predilection for the thumb and 2 cases were located on the hallux. Nail unit blue nevus mostly presented as a well-delimited blue spot of the lunula (9/11) and histologically was of the common type (10/11). There was no malignancy. CONCLUSION: Nail unit blue nevus is a rare asymptomatic benign entity, mostly acquired on the thumb or the hallux of women. The most frequent presentation is a painless blue spot on the lunula. Congenital blue nevi seem to only affect the paronychium. Main differential diagnosis is melanoma and histopathological examination is mandatory.

Overlapping DRESS and Stevens-Johnson Syndrome: Case Report and Review of the Literature.

Drug-induced severe cutaneous adverse reactions (SCARs) include acute generalized exanthematous pustulosis, drug reaction with eosinophilia and systemic symptoms (DRESS), and epidermal necrolysis (Stevens-Johnson syndrome [SJS], toxic epidermal necrolysis). The identification of the causal drug is crucial in order to avoid further exposure, but making the right differential diagnosis of the type of SCAR is equally important since treatment, follow-up, and prognosis of different SCARs are not the same. These syndromes are distinct entities with different clinical, biological, and histological patterns, but sometimes the early distinction between 2 SCARs can be extremely challenging, and overlapping conditions could therefore be taken into consideration, although true overlapping SCARs are very rare when using strict diagnostic criteria (described by the RegiSCAR group). Only a better understanding of the physiopathology of the SCARs could possibly explain these ambiguities and overlaps. We report a case of SCAR in an 86-year-old patient probably induced by allopurinol and simultaneously fulfilling the diagnostic criteria for DRESS and SJS, thus considered as an overlapping case of SCARs.

Phagocyte-specific S100A8/A9 is upregulated in primary Sjögren's syndrome and triggers the secretion of pro-inflammatory cytokines in vitro.

OBJECTIVES: To determine the role of S100A8/A9 in the pathogenesis of primary Sjögren's syndrome (pSS). METHODS: The serum levels of S100A8/A9 were determined in pSS patients and healthy controls by ELISA. The expression of S100A8/A9 in salivary glands was assessed by immunohistochemistry. The phenotype of S100A8+ and S100A9+ cells was identified using double immunofluorescence. The effects of S100A8/A9 on cytokine production by peripheral blood mononuclear cells (PBMCs) from pSS patients were determined in vitro by flow cytometry. The effects of pro-inflammatory cytokines on S100A8/A9 secretion were additionally investigated in vitro by ELISA in PBMCs from pSS patients and control subjects. RESULTS: Serum levels of S100A8/A9 were significantly increased in pSS patients compared to healthy controls. The tissular expression of S100A8 and S100A9, identified in professional phagocytes (neutrophils, monocytes and plasmacytoid dendritic cells), was increased in the salivary glands of pSS patients and correlated with focus score. In vitro, recombinant S100A8/A9 increased the production of IL-1ß, IL-6, TNF-α, IFN-γ, IL-10, IL-17A and IL-22 by PBMCs. The S100A8/A9-induced increase in TNF-α production in pSS patients was significant relative to controls. Furthermore, IL-1ß, TNF-α, IL-6, and IL-17A stimulated release of S100A8/A9 from PBMCs in pSS patients. CONCLUSIONS: S100A8/A9 is increased in pSS patients contributing to the in vitro increased production of pro-inflammatory cytokines. As such, S100A8/A9 in concert with other cytokines might contribute to the pathogenesis of pSS.