Ultrasonographic and resistance index evaluation of nails in psoriatic arthritis, psoriasis, and control groups: a cross-sectional study

Background Nail psoriasis occurs frequently in patients with psoriatic disease, it can lead to functional impairment, pain, discomfort, decreased quality of life and can also be a predictor for the development of arthritis. Early recognition of this condition can provide early and effective treatment and prevent structural impairment. This study aims to identify nail ultrasonographic characteristics in three groups: psoriasis (PsO), psoriatic arthritis (PsA) and controls patients, to determine if the ultrasonography (US) can identify early signs of nail psoriatic impairment or local inflammation. We conducted nail US to determine nail matrix resistance index (NMRI), nail bed resistance index (NBRI), and power Doppler (PD) and grayscale (GS) parameters in these 3 groups. Methods Single-center, cross-sectional study. GS, PD, and spectral doppler images of bilateral 2nd and 3rd fingernails were acquired from 35 PsO, 31 PsA, and 35 controls patients. An US equipment with an 18 MHz linear transducer for GS and 8.0 MHz for PD was used. PD, NMRI, NBRI, nail plate thickness (NPT), nail bed thickness (NBT), nail matrix thickness (NMT), and morphostructural characteristics of the trilaminar structure (TS) were evaluated in saved images, blind. Results Mean NMRI and NBRI did not differ between groups. Linear regression analysis detected no relationships between PsO or PsA and NMRI or NBRI. Nail PD grade did not differ between groups. Type I and IV TS changes were more frequent in PsO; types II and III changes were more frequent in PsA (p < 0.001). NPT was greater in PsA and PsO groups than controls: PsA 0.73 ± 0.14 mm, PsO 0.72 ± 0.15 mm, Controls 0.67 ± 0.10 mm (p = 0.001). Conclusion Echographic TS characteristics of the nail plate and NPT evaluated by GS are useful and can distinguish PsO and PsA nails from controls. NMRI, NBRI, and US nail microcirculation parameters could not distinguish psoriatic nails. Trial registration 72762317.4.0000.5327 (Certificate of Presentation of Ethical Appreciation – CAAE - Plataforma Brasil) Avaiable in https://plataformabrasil.saude.gov.br/login.jsf.

Onychomatricoma on the fourth toenail: A rare tumor in a rare localization

Onychomatricoma is a rare benign tumor of the nail matrix, characterized by finger-like projections that invade the nail plate. The fingernails of Caucasian women are most commonly affected. Because this tumor can easily mimic other more prevalent ungual diseases, it is crucial to be acquainted with its characteristic clinical and histopathologic features. The authors present a case of a 40-year-old man with an onychomatrichoma in the fourth left toenail, which was initially misdiagnosed and treated as onychomycosis.

Melanonychia striata: a case report

Melanonychia striata longitudinalis is a pigmented band in the long axis of the nail. The discoloration occured because of increase of melanin in the nail matrix. In most cases, especially in children, melanonychia striata is a benign condition. In this case report a 12-years-old male with melanonychia striata. Longitudinal excision was performed with histopathology examination to rule out malignancy and further management.

Porokeratosis of the Nail Unit: Case Series and Review

<b><i>Background:</i></b> The lesions of porokeratosis (PK) lead to skin atrophy and scarring as long as they spread centrifugally. PK affecting the nail unit is seldom described. <b><i>Objective:</i></b> The aim was to revise the previously reported cases of ungual PK and to present 3 new cases. <b><i>Methods:</i></b> A PubMed search was performed with the keywords “nail” and “porokeratosis.” Previously reported cases as well as 3 new cases are depicted in tables. <b><i>Results:</i></b> Only 11 cases of ungual PK were found; 3 new cases have been added. All patients presented with typical lesions of PK (Mibelli, isolated, segmental, or ostial eccrine types) that happened to affect nails due to nail matrix or nail bed compromise, resulting in mild to severe nail scarring, including irreversible anonychia. The present 3 case series contrast with the previous single case reports. <b><i>Conclusions:</i></b> PK affecting the nails is exceedingly rare. Changes in nails affected by PK are irreversible, since, as on the skin, this is a chronic scarring process.

Activation of the Melanocortin-4 receptor signaling by α-MSH stimulates nerve-dependent mouse digit regeneration

Background Expression of Mc4r in peripheral organs indicates it has broader roles in organ homeostasis and regeneration. However, the expression and function of Mc4r in the mouse limb and digit has not been fully investigated. Our previous work showed that Mc4r−/− mice fail to regenerate the digit, but whether activation of MC4R signaling could rescue digit regeneration, or stimulate proximal digit regeneration is not clear. Results We analyzed the expression dynamics of Mc4r in the embryonic and postnatal mouse limb and digit using the Mc4r-gfp mice. We found that Mc4r-GFP is mainly expressed in the limb nerves, and in the limb muscles that are undergoing secondary myogenesis. Expression of Mc4r-GFP in the adult mouse digit is restricted to the nail matrix. We also examined the effect of α-MSH on mouse digit regeneration. We found that administration of α-MSH in the Mc4r+/− mice rescue the delayed regeneration of distal digit tip. α-MSH could rescue distal digit regeneration in denervated hindlimbs. In addition, α-MSH could stimulate regeneration of the proximally amputated digit, which is non-regenerative. Conclusions Mc4r expression in the mouse limb and digit is closely related to nerve tissues, and α-MSH/MC4R signaling has a neurotrophic role in mouse digit tip regeneration.

Nd:YAG Laser in the Treatment of Nail Psoriasis: Clinical and Dermoscopic Assessment

Background: The Nd:YAG laser has emerged as a promising modality for the management of nail psoriasis owing to its ability for deep penetration of the skin surface, which has the advantage of destroying deep vessels. Objective: To assess the efficacy and safety of Nd:YAG laser in treating nail psoriasis. Methods: The present study was a randomized controlled study, conducted on 20 patients of both sexes (age older than 12 years) with mild to moderate psoriasis with nail involvement. We utilized facial telangiectasia parameters of Nd:YAG laser and beam diameter of 2.5 mm. Laser energy started with 110 J/cm2 in the first session and 130 J/cm2 in the rest of the sessions. Sessions were performed once monthly for up to 6 sessions. Results: We found no statistically significant difference in total Nail Psoriasis Severity Index (NAPSI) and nail bed scores before and after treatment among the treated group. However, there was statistically significant improvement in nail matrix score after treatment. On the other hand, the control group did not show any statistically significant changes for all scores throughout the study, except for the nail matrix score mean difference (0.35 ± 1.23 vs -1.00 ± 1.86 in the treated group). The degree of dermoscopic improvement was evident in the treated group (45% vs 25% in the control group). However, it was not statistically significant because of small sample size. The patients’ satisfaction and the external investigator’s assessment showed statistically significant negative correlation with total NAPSI mean difference in the treated group. Conclusion: The role of Nd:YAG laser in nail psoriasis is still controversial.

Pterygium Complicating Nail Psoriasis and Trachyonychia: Is It Rare?

Pterygium is an irreversible scarring of the nail matrix resulting in a split nail. The deformity is most often post-traumatic, though it can be the end result of aggressive inflammatory diseases involving the nail matrix like nail lichen planus, graft versus host disease, or autoimmune bullous disorders like cicatricial pemphigoid. It is thought to be a result of lymphocytic inflammation-mediated damage to the nail matrix, initiating a fibrotic process which slowly fuses the nail fold with the nail matrix and bed, destroying the nail plate. We report an interesting observation in a series of patients of various ages with nail and/or skin psoriasis, and trachyonychia associated with pterygium formation in multiple nails. Insidious progression to anonychia was also observed despite initiating adequate treatment. This report highlights the potential of irreversible nail damage occurring in reportedly benign nail conditions like psoriasis and trachyonychia, emphasizing the need for early recognition and aggressive management in such cases.