Brittle Fingernails

Efficacy and Acceptability of a New Water-Soluble Nail Strengthener Containing Pistacia lentiscus and Hyaluronic Acid to Improve the Appearance of Brittle Nails versus Untreated Nails: In vitro and Clinical Evidence

INTRODUCTION

Brittle nail syndrome is characterized by dry, weak, easily breakable nails that show inelasticity, splitting and overall nail plate fragility.

OBJECTIVE

This paper describes in vitro and clinical studies using bovine hooves designed to assess the efficacy, compatibility and acceptability of a water-soluble nail strengthener (WSNS), containing Pistacia lentiscus and hyaluronic acid, for the treatment of patients affected by brittle nails.

METHODS

In the in vitro study, the WSNS was tested versus placebo and a marketed product on bovine hoof membranes, applied once daily for 14 days for evaluation of firmness, viscoelasticity and thickness before and after applications. In a clinical study, 23 female subjects affected by brittle nails were included, and the WSNS was applied once daily for 3 months. Signs and symptoms were rated by the investigators and by the participants during treatment at 28 and 84 days with different methods and dermoscopic images. Subjective efficacy was evaluated by specific questionnaires.

RESULTS

In the in vitro study, the daily application of the WSNS and marketed product led to a significant increase in firmness index. In the clinical study, the nails on the treated hand presented an improvement in nail appearance and weakness, after 28 and 84 days of WSNS application, respectively. The nails not treated showed no improvement. The WSNS was well tolerated.

CONCLUSIONS

The WSNS containing Pistacia lentiscus and hyaluronic acid was shown to significantly increase nail firmness in the in vitro study. In the clinical study, WSNS significantly improved brittle nail appearance. The hydrosolubility and easy-to-apply format of WSNS were reported to be factors of a good compliance. We consider this product as an important tool to improve and reinforce the aspect of brittle nails.

Pathogenesis, Clinical Signs and Treatment Recommendations in Brittle Nails: A Review

Nail plate brittleness (or fragility) is a common complaint affecting up to 20% of the population, especially women over 50 years of age, with fingernail fragility being more prevalent than toenail fragility. Nail brittleness is characterized by nails that split, flake and crumble, become soft and lose elasticity. The main clinical presentations are: onychoschizia, onychorrhexis, superficial granulation of keratin and worn-down nails. According to causative factors, we can distinguish 2 forms of nail fragility (NF): a primary "idiopathic or brittle nail syndrome" form and NF secondary to different causes such as inflammatory nail disorders, infections, systemic diseases and general conditions, traumas and alteration of the nail hydration. Optimal management requires treatment of the primary cause of brittle nails, when possible. In idiopathic NF oral supplementation, vitamins (especially biotin, also known as vitamin B7), trace elements and amino acids (especially cysteine) have been reported to be useful. In addition, several products, such as topical moisturizers and lacquers could be considered to restructure the affected nail plate and to reduce psychological impacts of this common problem.

Water content and other aspects of brittle versus normal fingernails

BACKGROUND

Previous authors have claimed that dehydration of the nail plate causes brittle nails. Some experts claim that normal nails contain 18% water, and brittle nails contain less than 16%.

OBJECTIVE

We sought to test the hypothesis that brittle nails contain 2% less water than normal nails. We also examined the relationship between a number of health and behavioral variables and brittle nails.

METHODS

In all, 102 participants with either brittle or normal nails had two nails clipped and then analyzed for water content by a blinded investigator in the laboratory. Participants filled out a detailed questionnaire designed to reveal information about health and behavior.

RESULTS

The mean water content for normal nails was 11.90% and for brittle nails was 12.48%. There was no statistically significant difference between the two groups. The odds of having brittle nails was 3.23 times greater among participants who received a professional manicure (95% confidence interval 1.21, 8.59). The frequency of professional manicures was associated with the likelihood of having brittle nails. Frequency of hand moisturizer use was significantly associated with nail brittleness (95% confidence interval 1.35, 32.10). Family history was significantly associated with the likelihood of having brittle nails (95% confidence interval 1.65, 21.11).

LIMITATIONS

Analyzing nails from living participants is limiting because samples can only be collected from the distal unattached nail plate. A small subanalysis was performed and showed that the nails were losing water between the time of clipping and laboratory analysis. Therefore, our water percentage results may not be representative of in vivo nail plate water contents.

CONCLUSIONS

There was no significant difference in water content of brittle compared with normal nails.

Síndrome das unhas frágeis

A síndrome das unhas frágeis é queixa comum, caracterizada por aumento da fragilidade das lâminas ungueais. Afeta quase 20% da população geral, sendo mais comum em mulheres. Clinicamente se manifesta com onicosquizia e onicorrexe - distúrbios nos fatores de adesão intercelular das unhas se manifestam como a primeira, ao passo que alterações da matriz apresentamse com onicorrexe. Mesmo sendo tão usual e afetando os pacientes de maneira importante em seu cotidiano, o tratamento das unhas frágeis avançou pouco nas últimas décadas e ainda se baseia principalmente no uso da biotina.

Einfluss eines ureahaltigen Lackes auf die Nagelqualität

BACKGROUND

Urea is a well-known humectant. The aim of our study was to evaluate the in vivo effect of 10% urea lacquer on nail quality.

METHODS

60 healthy probands with brittle nails were included in a randomized, controlled study. The nail lacquer was applied once (n=30) or twice daily (n=30) on one hand for 28 days, while the other hand served as untreated control. Assessments included clinical evaluations and bioengineering measurements.

RESULTS

Application of the nail lacquer was well-tolerated and led to a significant clinical improvement of nail surface morphology, nail plate consistency, reflection of the nail plate surface, appearance of the cuticle and the nail fold. Sonographic nail density was slightly increased. No relevant changes were found in nail thickness and transonychial water loss.

CONCLUSIONS

Nail lacquer containing urea improves the cosmetic appearance of fingernails.

Brittle nail syndrome: a pathogenesis-based approach with a proposed grading system

Brittle nail syndrome is a heterogeneous abnormality, characterized by increased fragility of the nail plate. Brittle nails affect about 20% of the population and women are affected twice as frequently as men. The vast majority of patients experience brittle nails as a significant cosmetic problem and a substantial number indicate that these nail abnormalities are painful, impair daily activities, and may have a negative impact on occupational abilities. Pathogenic factors leading to brittle nails are factors that impair intercellular adhesion of the corneocytes of the nail plate or factors that cause a pathologic nail formation by involving the matrix. Clinical features of brittle nail syndrome are onychoschizia and onychorrhexis: the impairment of intercellular adhesive factors of the nail plate is expressed as onychoschizia, whereas the involvement of the nail matrix is expressed as onychorrhexis. Although impairment of life quality has not been evaluated for patients with brittle nail syndrome, the reduction of life quality in other nail problems has been studied and is evident. A proposed scoring system of key features of brittle nails is presented, and therapeutic approaches focussed on the pathogenic factors are discussed.

Cross-linked envelopes in nail plate in lamellar ichthyosis

BACKGROUND

Corneocytes of the nail plate, like those of the stratum corneum, generate cornified envelopes (CEs) of cross-linked protein that can be visualized readily after removal of non-cross-linked protein by detergent extraction. Defective CE formation occurs in epidermal scale and hair in transglutaminase 1 (TGM1)-negative lamellar ichthyosis (LI) and has been proposed as a diagnostic aid for this syndrome.

OBJECTIVES

(i) To ascertain whether TGM1 is important for CE formation in nail; (ii) to characterize CE abnormalities occurring in LI that may be distinguished from other types of inherited ichthyosis when nail samples are subjected to detergent extraction; and (iii) to evaluate the utility of nails as a diagnostic aid for LI.

METHODS

Nail samples were provided by nine patients previously classified as having TGM1-negative LI, four with other types of ichthyotic conditions and six normal controls. Samples were extracted extensively in sodium dodecyl sulphate under reducing conditions and examined by light and electron microscopy.

RESULTS

After extraction, defective CE cross-linking was visualized in epidermal corneocytes from seven of nine patients exhibiting TGM1-negative LI, whereas nail samples from patients with the other syndromes were normal. The defects in CE structure resembled those recently reported for LI scale, although in some cases residual CE and CE-associated structures were present.

CONCLUSIONS

Despite the paucity of clinical nail symptoms in LI, TGM1 activity is important for generation of normal CE in nail plate, consistent with its importance in protein cross-linking in interfollicular epidermis and hair. Lack of this activity leads to a strikingly aberrant appearance of CE in LI nail after detergent extraction that is evident ultrastructurally in a large majority of cases. Nail envelopes therefore could provide a useful diagnostic tool in distinguishing LI from other ichthyoses with overlapping clinical features.

Transonychial water loss: relation to sex, age and nail-plate thickness

The transonychial water loss (TOWL) was measured in 21 healthy volunteers with an evaporimeter, to establish the usefulness of this technique and study the influence of sex, age and nail-plate thickness. The median TOWL was 19.4 g/m2 h-1 and it decreased with increasing age (R = 0.51, P less than 0.018). The median transepidermal water loss (TEWLHAND) from the back of the hand was 16.0 g/m2 h-1 and from the dorsal side of the underarm (TEWLARM) it was 5.6 g/m2 h-1. The TEWLARM was significantly less than from any of the two other points studied (P less than 0.01), while there was no significant difference between the values obtained on the hand and the nail. TEWLARM had a median value of 6.4 g/m2 h-1 in men and 4.3 g/m2 h-1 in women (P less than 0.05) in this study. No significant correlation between nail-plate thickness, as measured by ultrasound 20 MHz A-scan, and TOWL was found. Measurements of TOWL are of interest and should be age-related. Further studies are needed to determine TOWL in various forms of nail pathology.