Nail lichen striatus: clinical features and long-term follow-up of five patients

Basic Concepts in Nail Pathology

ABSTRACT

Understanding nail pathology is complex for general pathologists and even for those dermatopathologists who do not receive many nail samples in their laboratories. In this article, we attempt to review some of the primary entities in nail pathology with the aid of modern interpretations of nail histology and embryology. We also provide diagrams that can aid in comprehending this field of pathology.

Causes of longitudinal nail splitting: a retrospective 56-case series with clinical pathological correlation

BACKGROUND

Split nail (SN) is a rare type of nail fragility syndrome, characterized by a longitudinal fissure involving the entire thickness of the nail plate. Longitudinal nail splitting may be caused by direct injury to the nail plate or matrix insult. Few articles have been published on the topic, most were related to the traumatic aetiology. Some case reports mention tumours and inflammatory disorders as other causes.

OBJECTIVES AND METHODS

The aim of this retrospective study was to analyse the clinical and histopathological features of 56 SN collected at the nail consultation of the dermatology department at Saint Pierre University Hospital in Brussels, between 1997 and 2019.

RESULTS

Fifty-six patients were included (34 women and 22 men) with median age of 44.2 years. The fingernails were 3.2 times more frequently affected than toenails, especially the thumb. The most frequent aetiologies were tumours (45.6%), inflammatory diseases (26.3%) and traumas (19.3%). Congenital (5.3%) and systemic disorders (3.5%) were rarer causes. Histopathological slide review confirmed that alteration of the nail matrix integrity causes split nail, resulting either from matrix stretching by an underlying tumour or from impairment of the keratinization process by inflammatory diseases, melanocytic tumours and Bowen's disease.

CONCLUSIONS

This study is the largest case series of longitudinal nail splitting to date. It is the first to gather nail disorders causing SN with their clinical pathological correlation. The most common causes are traumatisms, tumours and inflammatory disorders. Congenital and systemic disorders are rarer. Tumours are responsible for half of the cases from which one third are malignant, mainly melanoma. When facing a monodactylic SN, benign as well as malignant tumours should be ruled out before concluding to traumatic aetiology.

Pathology of the Nail Unit

This article discusses the histologic findings in key nail unit diseases, including inflammatory, infectious, and neoplastic conditions. The emphasis is on clinicopathologic correlates, best practices to demonstrate the relevant histopathologic features, and pitfalls in diagnosis. Understanding the pathology of these disorders enhances clinical acumen and may affect the choice of biopsy procedures and treatment measures, with the outcome of better clinical care for patients with nail disease.

Pediatric Nail Disorders

Many pediatric nail findings are normal variants and are no cause for alarm. Others represent congenital abnormalities or genetic syndromes for which there is no cure. Still others are inflammatory or infectious entities that require treatment. Pediatric nail disorders are reviewed, along with management.

Lichen Striatus with Nail Involvement in a 6-Year-Old Boy

We describe a 6-year-old boy with an asymptomatic linear eruption on the left index finger with mild erythema of the proximal nail fold, nail dystrophy, and subungual hyperkeratosis of the nail. A diagnosis of nail lichen striatus was made. The child was successfully treated with a topical corticosteroid. Because of its rarity, nail lichen striatus is often under-recognized. Physicians should be familiar with the nail involvement in individuals with lichen striatus so that an accurate diagnosis can be made and unnecessary investigations and treatment avoided.

Nail lichen striatus: Is dermoscopy useful for the diagnosis?

BACKGROUND/OBJECTIVES

Lichen striatus is a unilateral inflammatory dermatosis that rarely affects the nail unit. When the inflammation involves the nail unit, classic lichenoid nail changes are easily detectable, more often limited to only one portion of the nail. Usually the nail dystrophy coexists with periungual skin papules following Blaschko's lines, but it could also be an isolated feature. Because a nail unit biopsy presents difficulties in execution, especially in a child, the aim of our study has been to describe the nail unit dermoscopy features of lichen striatus hoping to provide a valid aid to clinicians in the diagnosing this rare disorder.

METHODS

We reviewed the images of five pediatric patients with a clinical diagnosis of lichen striatus. Data about sex, age, localization, predisposing/triggering factors, and associated disorders are reported.

RESULTS

The diagnosis of lichen striatus can be challenging as there are clinically overlapping features with related dermatoses. A common diagnostic pitfall occurs with inflammatory linear verrucous epidermal nevus and lichen planus. Involvement of only one part of the nail plate with linear longitudinal fissuring, ridging, and distal splitting, especially if seen with perionychial skin lesions, is characteristic of lichen striatus.

CONCLUSIONS

Nail lichen striatus is rare, and there is sparse published literature on it. When the changes in lichen striatus are limited to the nail, the diagnosis may easily be missed. We therefore believe that dermoscopy is an important diagnostic maneuver, which should be integrated into the evaluation of patients with potential lichen striatus, and in particular is helpful for clinicians unwilling or unable to perform a nail unit biopsy.

Nail Dystrophy in Patients with Atopic Dermatitis and Its Association with Disease Severity

Background

Nail dystrophy arises from various inflammatory dermatologic diseases. However, there have been few reports on the prevalence of nail abnormality in atopic dermatitis (AD) or on the relationship of this condition with the severity of the disease.

Objective

This study was intended to determine the prevalence and types of nail abnormalities associated with AD and to evaluate the relation between nail abnormalities and the severity of AD.

Methods

AD patients aged 2 to 19 who visited the outpatient clinic were thoroughly examined for nail abnormalities. Demographic information was collected and eczema area and severity index (EASI) score for severity of AD were checked.

Results

A total of 235 AD patients (children and adolescents) were investigated. There were 24 (10.2%) patients with nail abnormalities: transverse groove (Beau's line) (25.0%), nail pitting (16.7%), koilonychia (16.7%), trachyonychia (12.5%), leukonychia (12.5%), brachyonychia (8.3%), melanonychia (8.3%), onychomadesis (8.3%), onychoschizia (8.3%), and onycholysis (8.3%). There was no statistically significant difference in the total EASI score associated with development of nail abnormalities (p=0.236). However, when the EASI score was confined to the lower extremities, it showed a relation to the prevalence of toe nail dystrophy (odds ratio, 1.115; 95% confidence interval, 1.014~1.316; p=0.030).

Conclusion

Nail abnormalities in AD are thought to be caused mainly by pathologic change in the nail matrix region, and the EASI score confined to lower limbs, might be used as a predictor of toe nail changes in patients with AD.

Lichen planus and lichenoid dermatoses: Clinical overview and molecular basis

Deriving from the Greek word λειχήν for "tree moss" and the Latin word planus for "planar," lichen planus is a relatively uncommon and heterogeneous cutaneous disorder that typically develops in middle-aged adults. Despite the significant clinical burden associated with the disorder, little well-conducted molecular research has been undertaken, possibly because of heterogeneity impeding consistent and confident phenotyping. The multiple variants of lichenoid disease bear overlapping clinical and pathologic features despite manifesting as distinct clinical disorders. The first article in this 2-part continuing medical education series provides a comprehensive overview of the clinical and pathologic characteristics of cutaneous lichenoid dermatoses and links these manifestations to recent advances in our understanding of the underlying pathobiology of such diseases.

Lichen striatus with onychodystrophy in an infant

Lichen striatus with nail involvement is rare and is often unnoticed. Nail changes are often nonspecific but they are usually localized to one portion of the nail. Also single nail involvement and presence of skin lesions near the nail are often noticed. We report the case of an infant with lichen striatus and nail involvement.

Lichen planus and other lichenoid dermatoses: Kids are not just little people

Lichenoid dermatoses, a group of inflammatory skin conditions with characteristic clinical and histopathologic findings, range from common to rare. Classic lichen planus typically presents as pruritic, polygonal, violaceous flat-topped papules and plaques; many variants in morphology and location also exist. Other lichenoid dermatoses share similar clinical presentations and histopathologic findings. These include lichenoid drug eruption, lichen planus-like keratosis, lichen striatus, lichen nitidus, and keratosis lichenoides chronica. Epidemiologic characteristics vary among each lichenoid disorder. While classic lichen planus is considered a disease of adults, other lichenoid dermatoses may be more common in younger populations. The literature contains an array of reports on the variations in presentation and successful management of lichen planus and lichenoid dermatoses among diverse populations. Familiarity with the characteristics of each lichenoid dermatosis, rare or common within each patient population, is key to accomplishing timely recognition and effective management.

Tips to diagnose uncommon nail disorders

This article reviews 6 nail disorders that, although easy to diagnose, are misdiagnosed frequently by dermatologists and general practitioners. Diagnostic clues are emphasized to familiarize readers with features that indicate the correct diagnosis. We focus on two common tumors (onychomatricoma and onychopapilloma), two rare genetic conditions that can be diagnosed owing to nail changes (Darier disease and nail patella syndrome), and two uncommon acquired disorders (the yellow nail syndrome and lichen striatus).

Nail disorders in children: diagnosis and management

Nail disorders in children can be divided into seven categories. The first is physiologic alterations, which every physician should be aware of in order to reassure parents. These usually disappear with age and do not require any treatment. Among congenital and inherited conditions, the nail-patella syndrome, with its pathognomonic triangular lunula, should not be missed as recognition of the disease allows early diagnosis of associated pathologies. The most common infection is the periungual wart, whose treatment is delicate. Herpetic whitlow should be distinguished from bacterial whitlow as their therapeutic approaches differ. Dermatologic diseases encompass eczema, psoriasis, lichen planus, lichen striatus, trachyonychia, and parakeratosis pustulosa. Lichen planus, when it presents as in adults, is important to recognize because, if not treated, it may lead to permanent nail loss. Systemic or iatrogenic nail alterations may be severe but are usually not the first clue to the diagnosis. Beau lines on several fingernails are very common in children after temperature crest. Tumors are rare in children. Radiographic examination allows confirmation of the diagnosis of subungual exostosis. Other cases should undergo biopsy. Single-digit longitudinal melanonychia in children is mostly due to nevi. Its management should be tailored on a case-by-case basis. Acute trauma should never be underestimated in children and hand surgeons should be involved if necessary. Onychophagia and onychotillomania are responsible for chronic trauma.

Lichen striatus on adult

Lichen Striatus is an uncommon inflammatory skin eruption of unknown etiology. It rarely affects adults, and it is characterized by abrupt onset of coalescent papules, in a linear disposition, usually on the extremities. Histopathology shows lichenoid reaction involving follicles and glands. Occasionally, there is overlap with linear lichen planus and "blaschkitis", the main differential diagnoses. It is reported here the case of an adult woman with erythematous violaceous papules on the right side of the neck and face, diagnosed with lichen striatus by clinical and histopathological correlation. The atypical findings and the diagnostic difficulty are discussed.

[Lichen striatus with nail dystrophy in an infant]

BACKGROUND

Lichen striatus is an acquired eruption that develops in a linear pattern along Blaschko's lines, most commonly on the limbs. It is most often seen in children aged between 3 and 10 years. Nail involvement is uncommon. We report the case of an infant with lichen striatus and nail involvement.

CASE REPORT

A 10-month-old boy was referred for evaluation of acquired onychodystrophy on his right third and fourth fingers present for 2 months. On physical examination, lateral longitudinal ridging and splitting were seen on the right third and fourth fingernails with onychodystrophy. Linear bands of bright pink papules were seen on the inside and outside edges of the third and fourth fingers. Skin biopsy revealed a lymphocytic infiltrate in the superficial dermis with exocytosis and very few dyskeratotic cells, suggesting lichen striatus. Skin and nails lesions resolved spontaneously over 9 months.

DISCUSSION

Nail involvement in lichen striatus is uncommon and is frequently associated with typical skin lesions. Thirty cases have been reported in the literature since 1941. None of the subjects affected was younger than 2-years-old. Nail involvement was more frequent on the fingers, especially the thumb. As in the present case, longitudinal ridging, splitting and thinning with onychodystrophy are common clinical features of nail involvement. The diagnosis of lichen striatus is based on the presence of skin lesions and can be confirmed by biopsy.

Simultaneous lichen striatus in siblings along the same Blaschko line

Lichen striatus (LS) is an asymptomatic, spontaneously resolving linear dermatosis consisting of 2 to 4 mm flat topped papules following the lines of Blaschko. Two siblings presented with a simultaneous occurrence of LS along the same Blaschko line of the left upper extremity. Only four other cases of a simultaneous occurrence of LS in related siblings have been reported, but none of these have occurred in the same extremity. Although 10 years have passed since the last case report of this unique concurrent familial eruption, few discoveries have been made regarding its etiology. Several theories have been proposed including environmental agents, cutaneous injury, viral infection, hypersensitivity, and genetic predisposition. These theories are discussed along with retrotransposons, a possible new explanation for the pathogenesis of this and other Blaschko line disorders.

Lichen striatus in an adult following trauma

A 36-year-old man presented with a linear erythematous eruption along his right forearm and dystrophy of his right thumbnail. These changes had developed 2 weeks after his right thumb had been pricked by a pineapple leaf and evolved over a 6-week period. Histopathology revealed features consistent with lichen striatus. He complained of mild intermittent pruritus, which responded to moderate-potency topical corticosteroids. At 12 months the skin eruption had improved, but the nail changes persisted.

FOXN1 is critical for onycholemmal terminal differentiation in nude (Foxn1) mice

Nude mice have a mutation in the transcription factor Foxn1(nu), resulting in downregulation of hair keratins. Although hair follicles develop normally, the hair fibers become structurally weak, curl, and break off at the surface. Nails in nude mice are deformed, based on alterations of the onychocyte differentiation process. Elemental microanalysis of the nail plate reveals marked decreases in sulfur concentrations in the nude mouse nail plates. Immunohistochemistry shows a lack of keratin 1 expression in terminally differentiating keratinocytes of the nail matrix. Instead, the typical differentiation process of the matrix is altered toward an epidermis-like differentiation pattern, comprising the production of filaggrin-containing keratohyalin granules in cells resembling those of the stratum granulosum, which are never observed in normally haired mice. The nail plate has diffuse basophilic stippling. It is thinner than normal, weak, and in most Foxn1(nu)/Foxn1(nu) mice breaks where it separates from the hyponychium. These studies indicate that the Foxn1(nu) mutated gene has effects beyond downregulating keratin expression, including changes in filaggrin expression, and is critical for normal onycholemmal differentiation. The nails of nude mice provide new insights into the molecular controls of onychocyte differentiation, and they offer a useful model to investigate the pathogenesis of nail hypergranulosis, a common feature in human nail diseases.

Lichen striatus: clinical and laboratory features of 115 children

To analyze the clinical features, response to treatment, and follow-up of lichen striatus and any associated symptoms or disease, we designed a retrospective study involving 115 affected children at the Pediatric Dermatology Unit of the Department of Dermatology of the University of Bologna, Bologna, Italy. Between January 1989 and January 2000 we diagnosed lichen striatus in 37 boys and 78 girls (mean age 4 years 5 months). We studied their family history and the season of onset, morphology, distribution, extent, duration, histopathology, and treatment of their lichen striatus. We found that family history was negative in all our patients except for two pairs of siblings. The majority of children had the disease in the cold seasons; precipitating factors were found in only five cases. The most frequently involved sites were the limbs, with no substantial difference between upper and lower limb involvement. When lichen striatus was located on the trunk and face, it always followed Blaschko lines; in seven children the bands on the limbs appeared to be along the axial lines of Sherrington. In 70 cases, lichen striatus was associated with atopy. The mean duration of the disease was 6 months and relapses were observed in five children, and in one instance the disease had a prolonged course. Only a few case study series of lichen striatus in children have been reported and ours is the largest to date. The etiology of lichen striatus remains unknown in the majority of our patients. The confirmed association with atopy observed in our patients may be a predisposing factor. It has generally been accepted that lichen striatus follows the lines of Blaschko, and this distribution is a sign of both a topographic and a pathogenetic concept. In patients where lichen striatus is along axial lines, a locus minoris resistentiae, we suppose that this distribution may only be an illusory phenomenon in instances in which the trigger factor prefers this route, consisting of several successive Blaschko lines, but appearing as a single band.

Nail involvement in lichen striatus

Nail involvement in lichen striatus is nearly always accompanied by skin lesions. A case of childhood lichen striatus involving the thumb nail is presented.

[Lichenoid eruptions in the child]

Lichenoid eruptions are represented by lichen planus and lichen striatus. They are characterized clinically by a papulous eruption, and histogically by a dermal superficial infiltrate of lymphocytic cells and a cytotoxic reaction directed against basal keratinocytes. The main differential diagnosis is hamartoma, the differentiation being important because of the possible association of haemartoma with malformations.

Localized lichen sclerosus with nail loss

A 52-year-old woman who developed a pale sclerotic second left toe with loss of the nail plate is described. Biopsy showed changes of lichen sclerosus. There were no other skin or genital lesions present.