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.

Differential Diagnosis of Retronychia, Onychomycosis and Onychomadesis.

Background: In rare dermatology cases the differential diagnosis is challenging, e.g. when one nail is growing below another, the provisional diagnosis could be confusing. It may present as chronic paronychia, candidiasis, bacterial infections, rheumatoid arthritis, psoriasis, subungual tumours, or cysts. Case description: We present a case of iatrogenic rupture of the nails of both big toes following a commonly known recommendation from physiotherapists in the initial stages of hallux valgus or chronic arthritis by using kinesio tape to prevent the big toe from fixation in the valgus position. The initial provisional diagnosis of retronychia was revised, and a final diagnosis of onychomadesis was made. The patient's complaint was solved after around one year without any specific therapy. Conclusion: The differential diagnosis for onychomadesis needs a careful and detailed history that may prevent a patient from a frightening diagnosis and painful, long-lasting treatments. LEARNING POINTS: The differential diagnosis of retronychia, onychomycosis and onychomadesis is challenging.Both onychomadesis and retronychia share a common pathophysiologic mechanism.A careful and detailed history prevents a patient from a frightening diagnosis and painful, long-lasting treatment of nail disorders.

Imaging features for the evaluation of skin and nail infections.

Clinical manifestations of dermatological and musculoskeletal conditions can sometimes overlap, leading to confusion in diagnosis. Patients with nail and skin infections may undergo imaging examinations with suspicions of muscle, tendon, or joint injuries. Dermatological infections often involve soft tissues and musculoskeletal structures, and their etiology can range from fungi, bacteria, viruses, to protozoa. Relying solely on physical examination may not be sufficient for accurate diagnosis and treatment planning, necessitating the use of complementary imaging exams. The objective of this paper is to present and discuss imaging findings of the main infectious conditions affecting the nail apparatus and skin. The paper also highlights the importance of imaging in clarifying diagnostic uncertainties and guiding appropriate treatment for dermatological conditions.

Retronychia in children: A case series.

BACKGROUND: Retronychia is characterized by proximal ingrowing of the nail plate into the proximal nail fold. It is always associated with the presence of two or more overlapping nail plates under the proximal nail fold, clinical signs of chronic proximal paronychia refractory to antimicrobial treatment, and a yellowish nail that does not grow. It mainly affects young female adults, with less than 30 pediatric cases described in the literature so far. METHODS: Retrospective and observational study of patients between 0 and 18 years with a clinical and/or ultrasound diagnosis of retronychia attending a pediatric dermatology service between December 2020 and January 2022. RESULTS: We identified 9 patients with retronychia, 7 girls and 2 boys. In all cases, the hallux nails were affected with 5 unilateral and 4 bilateral cases. On physical examination we observed the following signs: thickened and opaque nail plate (one patient), yellowish nail plate (7 patients), double nail plate (6 patients), and erythema with edema, pain, and suppuration of the proximal nail fold (7 patients). Ultrasound was performed in 7 patients and specific findings of retronychia were found in 5 of them. All patients received topical treatment and were referred for the appropriate surgical treatment. To date, only one patient underwent nail avulsion, which was followed by complete recovery. CONCLUSIONS: Retronychia is underdiagnosed, particularly in the pediatric population. We present a series of 9 cases of retronychia in children, with clinical and ultrasonographic findings consistent with those of adults. We emphasize the importance of recognizing this entity, which will allow early and adequate treatment.

Retronychia: A Misdiagnosed Cause of Paronychia.

Retronychia refers to the embedding of the nail into the proximal nail fold. Patients present with chronic paronychia in the setting of disrupted nail growth. Nail avulsion is curative and unlike other forms of ingrown nails, it does not tend to recur. We report a case of retronychia who presented with pain and swelling around bilateral great toes. Further examination showed growth of overlapping nail plates, which led to the diagnosis of retronychia. This article emphasizes the clinical features and treatment options available for retronychia, thereby avoiding misdiagnosis.

Radiological Imaging of Nail Disorders (PART II) - Radiological Features of Nail Disease.

We have seen that radiological techniques like digital x-ray, high-frequency ultrasonography (USG), computed tomography (CT), and magnetic resonance imaging (MRI) have their unique roles in assessing a complex anatomical structure like the nail unit. Broadly speaking, USG and MRI help evaluate soft tissue components well; while, radiographs and CT scans help assess bony lesions better. In the second part of this review, salient radiological features of various nail disorders, as seen on these modalities are detailed. The radiological features mostly play a supportive role and help rule out differential diagnoses. However, in some diseases like retronychia and some nail tumors, radiological findings help clinch the diagnosis. The diagnostic features as well as the investigative modality of choice for a particular disease are highlighted based on the best level of evidence (LoE) available. This narrative review includes both infectious and non-infectious nail unit diseases, with special emphasis on nail unit tumors.

Chronic Retronychia: Nonsurgical Treatment.

Introduction: Retronychia is a particular form of post-traumatic ingrown nail associated with repeated microtrauma of the underside of the proximal nail fold. It is caused by the nail embedding backward into the underside of the proximal nail fold, forming multiple generations of nail plate. Methods: The study aims to evaluate the results of a novel nonsurgical treatment of retronychia. A review was performed on 20 patients who underwent the treatment, 16 having suffered from a chronic form of the condition, with the remaining 4 being afflicted with retronychia for less than a year prior to treatment. Results: The treatment was a combination of eliminating the proximal sharp edge of the uppermost nail layer and thinning of the nail with fraises and drills of various sizes. This therapy was repeated every 7-14 days. The patients came for checkup every 6 weeks. Treatment duration varied from 2 to 14 months. The rate, at which the appearance of a healthy nail occurred depended on the length of the intact nail layer below the part of the nail affected by retronychia, the age of the patient, and cofactors such as obesity, diabetes, etc. The treatment result in our case study was completely healthy nail growth without relapse of retronychia in all the 20 patients for a follow-up period of 18 months. Conclusion: By combining a healthy nail growth and the simultaneous protection of the nail, we were able to achieve a normal nail in all cases. In order to maintain the achieved results, we recommended our patients to continue wearing protective tubes whenever they would wear closed shoes because recurrence of retronychia may occur even after minimal trauma.

Optimal diagnosis and management of common nail disorders.

Nail conditions are not only aesthetic concerns, and nail changes may be a clue to an underlying systemic diseases or infection. Without timely treatment, nail diseases can continue to worsen and significantly impair performance of daily activities and reduce quality of life. Examination of the nails is essential at every medical visit, and may uncover important findings. Brittle nail syndrome, onychomycosis, paronychia, nail psoriasis, longitudinal melanonychia, Beau's lines, onychomadesis and retronychia are common nail disorders seen in clinical practice. These conditions stem from infectious, inflammatory, neoplastic and traumatic aetiologies. Though each nail condition presents with its own distinct characteristics, the clinical findings may overlap between different conditions, resulting in misdiagnosis and treatment delays. Patients can present with nail plate changes (e.g. hyperkeratosis, onycholysis, pitting), discolouration, pain and inflammation. The diagnostic work-up of nail disease should include a detailed history and clinical examination of all 20 nail units. Dermoscopy, diagnostic imaging and histopathologic and mycological analyses may be necessary for diagnosis. Nail findings concerning for malignancy should be promptly referred to a dermatologist for evaluation and biopsy. Nail disease management requires a targeted treatment approach. Treatments include topical and/or systemic medications, discontinuation of offending drugs or surgical intervention, depending on the condition. Patient education on proper nail care and techniques to minimize further damage to the affected nails is also important. This article serves to enhance familiarity of the most common nail disorders seen in clinical practice. It will highlight the key clinical manifestations, systematic approaches to diagnosis and treatment options for each nail condition to improve diagnosis and management of nail diseases, as well as patient outcomes.Key messagesNail disease is not only a cosmetic issue, as nail changes can indicate the presence of a serious underlying systemic disease, infection or malignancy.Nail pain and changes associated with NP are physically and emotionally distressing and may contribute to functional impairment and diminished quality of life.LM is a hallmark sign of subungual melanoma and this finding warrants further investigation to rule out malignancy.

Treatment of retronychia: A systematic review and suggested treatment algorithm.

Retronychia is an inflammatory disorder typical of the great toes characterized by arrested nail growth, ingrowth of the nail plate into the proximal nail fold and paronychia. There is no standardized treatment for retronychia, and its management should be weighed based on the severity stage, treatment modality, and clinical outcome. In this paper, a systematic review of the literature was performed to assess all published data regarding the treatment of retronychia. A total of 231 patients from 24 studies were included in the analysis. Conservative management was adopted in mild-intermediate forms, consisting of medical (topical or intralesional high-potency corticosteroids) and podiatric treatment (taping, clipping back the onycholytic plate, orthosis), leading to a global cure rate of 41.2%, with no reported side effects. Non-conservative management, that is, chemical or surgical avulsion of the nail plate, proved resolutive in 71.2% of cases. Surgical avulsion of the nail plate produced the highest cure rate (78.2%), but was burdened by 9.6% of long-term sequelae, mainly nail dystrophies. A decision-making algorithm was designed to give clinicians treatment indications based on the severity stage of retronychia, treatment invasiveness, and possible clinical outcomes.

Superficial Acral Fibromyxoma: Clinicopathologic Analysis of Five Cases.

Superficial acral fibromyxoma is a relatively rare benign slow-growing soft-tissue tumor, first described by Fetsch's group [Hum Pathol. 2001;32:704-14]. Since then, around three hundred publications have concerned this relatively new entity. The tumor involves peri- and subungual regions of fingers and toes in middle-aged adults with slight male predominance. This acral fibrous tumor is poorly known, and in certain cases, histology results may suggest myxoid dermatofibrosarcoma, which carries a completely different prognosis. In this article, we discuss the clinicopathologic features of this acral fibrous tumor through the report of 5 cases including 1 particular clinical presentation that revealed as a retronychia in a young woman.

Retronychia-an uncommon cause of chronic proximal nail fold inflammation.

Retronychia is defined as nail plate ingrowth into the proximal nail fold causing pain and perionyxis. We report on a case series of seven patients seen from 2001 to 2020 (mean age 20 years). Xanthonychia was observed in all nails. Total nail avulsion was performed in eight nails. Complete remission was obtained in 100%. During follow-up for up to 24 months, no relapse occurred.

Retronychia: A Paradigm Shift?

Retronychia is an increasingly known cause of paronychia. It was classically regarded as an indication for total nail plate avulsion, but recent case series have questioned the real need for this approach. In order to establish a proper recommendation for patients presenting with retronychia, we retrospectively reviewed all articles with retronychia case reports. Total nail plate avulsion is still the most efficient treatment option. Topical steroids and other noninvasive approaches can be useful in some early, mild cases, but further prospective studies are needed in order to access their efficacy.

Superficial Acral Fibromyxoma, Appearing as Retronychia: A Rare Clinical Entity.

We report a case of a subungual superficial acral fibromyxoma (SAFM) in a 37-year-old male patient who presented with a persistent chronic proximal paronychia of the big toenail of the right leg. Our clinical diagnosis was retronychia, an often misinterpreted condition, which must be suspected in cases of persistent paronychia, especially in the setting of trauma. The nail plate avulsion revealed a subungual tumor, which was surgically excised. Histopathology in combination with immunohistochemistry revealed features suggestive of SAFM. The follow-up examination of the patient showed no recurrence 9 months after the surgery.

Intralesional steroid treatment for the intermediate stage of retronychia: A pilot study.

Retronychia describes the proximal ingrowing of the nail plate. In the early stage, topical steroids are the gold standard therapy, while in the late stage surgical treatment is mandatory. We identified an intermediate severity stage of retronychia, where the topical treatment alone is ineffective and surgery is avoidable. Intralesional steroids turn the best treatment in these patients. A pilot study consisting of a 3-month treatment period and 9-month follow-up time was designed to evaluate the treatment outcome to intralesional steroid injections in patients affected by the intermediate-stage of toenail retronychia. The complete recovery of retronychia-associated nail abnormalities was observed in 27/28 recruited patients at the end of the treatment phase. Paronychia, nail plate discoloration, proximal nail fold (PNF) elevation, and discharge were reduced (P < .01) after one steroid administration, while nail regrowth became significant after two sessions. No significant difference in terms of clinical outcome was found, while pain VAS score and intra-operative pain evaluated with Wong-Baker faces scale were higher in the female group (P < .01). Limitation Lack of control group of patients. Despite its temporary effect, the intralesional triamcinolone injection is an effective, cheap, and safe treatment especially for the intermediate stage of retronychia.

Skin and nails abnormalities in a patient with ZTTK syndrome and a de novo mutation in SON.

Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome is a rare, severe, and recently described multisystem developmental disorder characterized by delayed psychomotor development and intellectual disability, characteristic facial features, hypotonia, poor overall growth, and visual abnormalities. Mucocutaneous manifestations have not been reported so far among individuals with ZTTK syndrome. Herein, we present a patient with ZTTK syndrome due to a de novo mutation in SON gene, who has dental abnormalities and retronychia of the toenails. We suggest that mucocutaneous features may be a part of the phenotype.