Classification of Retronychia: A Narrative Clinical Review.

Background: A retronychia classification system is overdue considering the most recent publications. Using the keyword "retronychia", publications with a narrative literature review were selected from PubMed/MEDLINE, EMBASE and Google Scholar, adding a few select papers. Summary: This article proposes a theoretical pathophysiological basis for retronychia. Several factors alter the clinical picture of retronychia: length and periodicity of backward displacement, duration of disease, intensity of paronychia, presence and type of nail stacking (polymeronychia), and remodeling of the nail apparatus (elevation of the proximal nail, nail bed shortening, retroversion of the distal nail fold and acquired malalignment). Key Messages: With these factors in mind, we propose a new classification system for retronychia: A standing for acute, O for ongoing, and C for chronic. We believe this easy system may increase the diagnostic acuity for the disease and its understanding.

Review and Therapeutic Approach to Malalignment of the Great Toenails: A Common Condition That Is Uncommonly Diagnosed.

BACKGROUND: Malalignment of the great toenails is a common nail disorder that is uncommonly recognized in general practice. OBJECTIVE: Review available literature on lateral malalignment of the great toenails to increase awareness of this underdiagnosed condition and provide management recommendations. METHODS: A PubMed search was conducted using the terms "congenital malalignment toenail" and "malalignment great toenail". All articles were reviewed, and all relevant articles were included in this analysis. RESULTS: Thirty-four distinct articles encompassing 117 patients with similar clinical findings: lateral deviation of the great toenails with yellow brown dyschromia, thickening, and scalloping. LIMITATIONS: Description of malalignment and terminology can vary, which may have led to exclusion of some relevant articles. CONCLUSION: Lateral malalignment is a common nail condition that is underappreciated and often misdiagnosed in general dermatologic and medical practice. This review aims to increase awareness to facilitate better care of these patients.

Squamous cell carcinoma of the nail apparatus: Histopathology and immunohistochemistry correlation study.

BACKGROUND: Nail squamous cell carcinoma (NSCC) is the most frequent ungual malignant tumor, but its incidence remains low. The histopathological description is sparse. We aim to characterize NSCC histopathological aspects, search for a correlation with clinical subtypes, and investigate immunohistochemistry expression of p16, p53, and Ki67. METHODS: This retrospective study collected NSCC diagnosed in our dermatology department between 2007 and 2021. The histopathological features were correlated with the clinical signs and immunohistochemistry. RESULTS: A total of 48 patients were included, and immunohistochemistry was available for 36 of them. Two histopathological patterns became prominent: a blue-basaloid type characterized by koilocytosis (p < 0.001), and a pink-keratinizing type. Mean ages were similar when comparing basaloid and periungual versus keratinizing and subungual (p < 0.001). p16 was positive in 31 of 36 cases: 18 basaloid and 13 keratinizing (p = 0.167). p53 and Ki67 were all abnormal. CONCLUSIONS: Our study described two histopathological NSCC subtypes and associated them with the two clinical subtypes: the blue-basaloid type, HPV-induced, in situ, of periungual localization in younger males; and the pink-keratinizing type, non-HPV-induced, invasive, of subungual site, in elderly. Immunohistochemistry was not contributing on its own, but p16 positivity associated with basaloid histopathological profile helps support HPV etiology.

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.

Dermoscopic Nail Changes in Psoriasis, Lichen Planus, and Lichen Striatus.

Background: Onychoscopy is a noninvasive method helpful in diagnosing nail disorders. The aim of the study was to review literature on the usability of onychoscopy in nail psoriasis, nail lichen planus, and nail lichen striatus. Summary: Onychoscopic features of nail psoriasis are pitting, onycholysis with erythematous border, salmon patches, splinter hemorrhages, dotted vessels in lateral and proximal folds, and hyponychium. Onychoscopic features of nail lichen planus are onychorrhexis, onycholysis, longitudinal melanonychia, and red lunula. The literature on the usability of onychoscopy in nail lichen striatus is scarce. Keynotes: Onychoscopy facilitates evaluation of nail abnormalities compared to the clinical examination. Lunular alterations, salmon patches, erythematous border of onycholysis as well as splinter hemorrhages in nail psoriasis are better visualized with onychoscopy compared to the naked eye. Onychoscopy enhances detection of melanonychia, dyschromia, and lunular changes in nail lichen planus. Onychoscopic features are different in fingernails and toenails.

Onychoscopy (nail dermoscopy) is a noninvasive method used in diagnosing of nail disorders. In this review, we evaluated if onychoscopy may be helpful in diagnosing inflammatory nail disorders such as psoriasis, lichen planus, and lichen striatus. Nail psoriasis can be characterized with the presence of pitting, salmon patches, splinter hemorrhages, onycholysis with or without erythematous border and dilated vessels in the hyponychium on onychoscopy. Onychoscopy of nail lichen planus shows the presence of longitudinal ridging and splitting (onychorrhexis), splinter hemorrhages, longitudinal melanonychia as well as red lunula (distal part of nail matrix). The data on onychoscopy in nail lichen striatus are scarce. Onychoscopy is a helpful tool in visualization of nail abnormalities, with most of the features better visualized with onychoscopy compared to the naked eye.

Onychomatricomas: A 41-Case Series to Assess Surgical Outcome.

BACKGROUND: Onychomatricoma (OM) is a rare benign tumor of the nail matrix. Treatment is surgical, but data are currently limited. OBJECTIVE: To review all cases of OM operated in their department and to assess the link between the location on the nail plate, the thickness and width of the lesion, and the postoperative outcomes. MATERIALS AND METHODS: Records of 62 patients were retrieved from their department's database over a 25-year period (1998-2023). RESULTS: Of the 62 patients, 41 were eligible. In total, 58% of OM occupied a width of a quarter of the nail plate, 51% had a plate thinner than 3 mm, and 51% were laterally located. Of the 41 patients included, 29 had a tangential excision and 12 underwent lateral longitudinal excision. Among the tangential excision group, 71% had normal nail regrowth. Onychomatricoma thicker than 3 mm and involving the total nail plate width had a sequelae in 60% of cases. CONCLUSION: Tangential excision of onychomatricomas allows a normal nail regrowth in 71% of cases. The risk of sequelae increases for tumors thicker than 3 mm and involving the total nail plate width. Medial or lateral location seems to have no influence.

Green nail: Etiology and treatment of chloronychia.

"Green nails" or chloronychia results from an infection mostly caused by Pseudomonas sp. but also from other bacterial or fungal contamination. Its presents as a typical triad: green discoloration of the nail plate with proximal chronic paronychia and disto-lateral onycholysis. In a moist environment, Pseudomonas colonizes onycholysis of any origin (traumatic, inflammatory or tumoral). Nail color varies from pale green to dark green, almost black. Treatment consists in cutting of the detached nail plate, brushing the nail bed with a 2% sodium hypochlorite solution twice daily accompanied by moisture eviction by wearing latex gloves over cotton ones for all daily household tasks.

Nail cosmetology.

Nail cosmetics is enjoying growing success due to recent technological advances. Manicures can be responsible for mechanical, infectious or allergic adverse effects. Nail cosmetics (e.g., nail varnishes, acrylic false nails, light-curing gels, and adhesive false nails) incorporate substances that harden after solvent evaporation or after polymerization. Allergic reactions can occur, remotely with conventional varnishes and locally with polymerizing substances. Artificial nails incur a risk of carrying infectious agents which can cause serious infection, and should not be used by caregivers. Recently, there has been a worrisome increase in the frequency of acrylate allergy, due to the appearance of home kits and lack of information in the general public. The infectious, allergic and toxic risks incurred by consumers and professionals regarding manicure or pedicure treatments and the application of nail cosmetics are the subject of recommendations and monitoring measures.

Nail disorders to be kept in mind.

Recognizing and diagnosing the most common nail diseases is essential, to be able to guide patients and provide appropriate treatment. However, uncommon nail disorders should not be neglected, in order to avoid inadequate treatment and above all to ensure that no severe underlying disorder, with severe prognosis, is overlooked.

Examination of the nails: Main signs.

Understanding the anatomy of the nail apparatus is a prerequisite for diagnosing and managing various nail disorders. The latter may be associated with systemic pathologies, or accompany infectious, inflammatory, tumoral, toxic or traumatic dermatoses. Before attempting to identify the cause, a rigorous clinical examination should be conducted to screen for elementary lesions that may affect general nail shape, nail surface, subungual attachments, periungual soft tissue or nail color. All of these guide differential diagnosis.

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.

Surgery for benign nail tumor.

The vast majority of tumors in the nail apparatus have a different clinical presentation and course from their equivalents on the skin. Some, such as onychomatricoma and onychopapilloma, are unique to the nail and others, such as superficial acral fibromyxoma, have a tropism for the nail apparatus. As a rule, benign lesions respect the general architecture of the nail apparatus, whereas malignant tumors are destructive. Treatment is always surgical and good knowledge of the anatomy and the procedures is mandatory in order not to induce postoperative nail dystrophy.

Chronic spontaneous urticaria: Evidence of systemic microcirculatory changes.

BACKGROUND: Chronic spontaneous urticaria (CSU) is a chronic inflammatory skin disease where activation of endothelial cells (ECs) at sites of skin lesions leads to increased blood flow, leakage of fluid into the skin, cellular infiltration, and vascular remodeling. To understand the disease duration and the sometimes vague systemic symptoms accompanying flares, the objective of this study was to examine if CSU comes with systemic vascular changes at the microcirculatory level. METHODS: We investigated CSU patients (n = 49) and healthy controls (HCs, n = 44) for microcirculatory differences by nailfold videocapillaroscopy (NVC) and for blood levels of the soluble EC biomarkers serum vascular endothelial growth factor (VEGF), soluble E-selectin, and stem cell factor (SCF). Patients were also assessed for clinical characteristics, disease activity, and markers of autoimmune CSU (aiCSU). RESULTS: CSU patients had significantly lower capillary density, more capillary malformations, and more irregular capillary dilations than HCs on NVC. Serum levels of VEGF, soluble E selectin and SCF were similar in CSU patients and HCs. CSU patients with higher VEGF levels had significantly more abnormal capillaries. Patients with markers of aiCSU, that is, low IgE levels or increased anti-TPO levels, had significantly more capillaries and less capillary dilations than those without. CONCLUSION: Our results suggest that CSU comes with systemic microcirculatory changes, which may be driven, in part, by VEGF.

Three atypical/malignant onychopapillomas in a 52-case series with immunohistochemical study.

BACKGROUND: Onychopapilloma (OP) is a benign tumor of the nail. Haneke reported one case of malignant OP in 2021. No systematic immunohistochemistry study has been conducted on OP. The aim of our study was to identify possible malignant OP in our series of OP and to describe the immunohistochemical expression of p16, p53, and Ki67 in typical and atypical/malignant ones. METHODS: Ninety-one cases were available for pathological review. Immunohistochemical analysis could be performed on 52 cases. RESULTS: In 88 of 91 cases, the diagnosis of OP was confirmed. Three atypical/malignant cases were observed. No OP expressed p16. A normal p53 expression was observed in two thirds of the cases, an abnormal increased p53 expression in one third, including the three atypical cases. A normal Ki67 expression was observed in 84% of the cases, an abnormal Ki67 expression with focal heterogeneous expression in the suprabasal layers in 6% and in all suprabasal cell layers in 10%, including the three atypical cases. CONCLUSIONS: The diagnosis of atypical/malignant OP may be underestimated. The expression of Ki67 and p53 in these tumors differs from the expression observed in conventional OP. The absence of p16 expression confirms that human papillomavirus does not play a role in the etiopathogenesis of OP.

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.

Kaposi Sarcoma of the Nail Unit: A Case Report and Review of the Literature.

Introduction: Kaposi sarcoma is an angioproliferative neoplasm. Its manifestations are well known but nail involvement seems extremely underreported. Case Presentation: A 55-year-old man presented with a 6-month history of a growing subungual tumor affecting the third right toe. After surgical excision, histological examination revealed a Kaposi sarcoma. Discussion: We report a case of Kaposi sarcoma with nail involvement of only one toe as the first and unique manifestation, which is exceptional.

Chronic Spontaneous Urticaria in Belgium: Deciphering the Clinical Profile and Treatment of Patients Visiting an Urban City Immunology Department.

BACKGROUND: Chronic urticaria (CSU) is a chronic inflammatory mast cell-driven disorder of which reliable clinical data in Belgium are lacking. This study focusses on clinical characteristics of CSU patients presenting at an urban Immunology-Allergology department. METHODS: Outpatients with CSU were included from 2018 to 2021. Clinical characteristics, Dermatology Life Quality Index (DLQI) and Urticaria activity score (UAS7) were collected by thorough anamnesis and questionnaires. Furthermore, patients underwent provocational testing, an autologous serum skin test (ASST) and a blood analysis. RESULTS: The study included 49 CSU patients and 20 non-CSU subjects. CSU was distributed differently with age and sex, showing higher numbers in female patients below the age of 46 years. 67% of CSU patients had accompanying angioedema of which 9% were reported genital. CSU patients scored a mean 8/30 on their DLQI questionnaire. There was no significant difference in immunoglobulin E (IgE), C-reactive protein, and tryptase levels between CSU patients and controls. Oral glucocorticosteroids were prescribed in 23% of CSU patients during their disease course though only half of these patients had a severity grade 4 CSU. In 82% of the included CSU patients, Urticaria Control Test (UCT) scores were below 12. When we hypothetically considered low IgE levels and high IgG anti-thyroid peroxidase levels as differentiation marker for autoimmune (ai)CSU and non-aiCSU, we found that 4% of all included CSU patients could be considered aiCSU. CONCLUSION: Generally, the inner-city population displayed the same clinical characteristics, as previous cohorts from Northern Europe. The relatively high rate of CSU patients receiving oral glucocorticosteroid treatment for their disease though not always classified as severe, underlines the need to train doctors of various specialties in the treatment algorithms of CSU. Furthermore, by looking at potential autoimmune characteristics, our findings open perspectives on the identification of new routinely used clinical parameters for the detection of aiCSU, a relatively small immunological subtype of CSU.