Onychomadesis with Lichen Planus: An Under-Recognized Manifestation

Thiamethoxam-Induced Subclinical Onychomadesis

Introduction

Irritant contact dermatitis affecting the nail unit may lead to nail matrix damage and onychomadesis, which may initially be subclinical, becoming overt later. We describe a patient who developed these changes after using a chemical pesticide.

Case Presentation

A 52-year-old woman presented with discoloration of the nails of both hands of two days' duration, associated with mild digital pain. She had used an over-the-counter insecticide product containing thiamethoxam (a broad-spectrum systemic insecticide) for her houseplants, preceding the nail changes. Examination revealed onycholysis and subclinical onychomadesis involving multiple fingernails as well as toenails. Onychoscopic examination showed proximal nail plate separation with an erythematous regular border. Histopathology showed an essentially normal nail plate with spongiosis, epidermal cell necrosis, and hypergranulosis. However, there was no evidence of bacterial or fungal infection, and dermal inflammation was mild. The patient was diagnosed with thiamethoxam-induced irritant dermatitis with subclinical onychomadesis and was advised to take general precautions with avoidance of any further contact with the insecticide. She was managed with topical steroids and emollient; however, on follow-up, she developed green nails, with progression to overt onychomadesis in some nails. Additionally, onychomycosis was observed in few nails in the long-term, which needed to be treated.

Conclusion

Thiamethoxam is an over-the-counter broad-spectrum insecticide used for houseplants, but its safety data does not mention acute adverse effects on nails, which was a novel finding in our patient. The safety data does mention the use of gloves for preparing and administering the product. Secondary bacterial and fungal infections, which can occur after the initial insult, further worsen the prognosis.

Nail lichen planus: A review of clinical presentation, diagnosis and therapy

Lichen planus is a multifaceted disease of complex etiopathogenesis. Nails are involved in up to 10% of patients with lichen planus. Although most cases are mild, serious consequences may occur due to rapid progression of the disease, the high risk of scarring, and the resulting irreversible damage to the nail structure. Permanent damage of at least one nail occurs in approximately 4-12% of patients with nail lichen planus. In this narrative review, we emphasize the pathophysiology of nail lichen planus, the emergent nature of the disease, and the spectrum of different clinical manifestations. Diagnosis of nail disease in general, and of nail lichen planus in particular, is rapidly evolving. This review provides a comprehensive account of the non-invasive and invasive diagnostic techniques and treatment options reported in the literature, with emphasis on the efficacy and safety of the drugs used, the associated evidence, and the factors to be taken into account in planning and providing adequate treatment. The role of aesthetic and camouflage options is also summarized.

Histopathological evaluation of nail lichen planus: A cross-sectional study

INTRODUCTION

Up to 10% of patients with lichen planus (LP) have nail involvement; still there is a paucity of studies on histopathological features. Nevertheless, nail biopsy is the diagnostic standard, especially for isolated nail LP.

METHODOLOGY

Nails of 45 patients with nail LP were evaluated clinically and biopsies taken from most involved nail (25 nail bed and 20 matrix biopsies). Correlation of clinical and histopathological features was also done.

RESULTS

The mean age of the study group participants was 36.91 ± 18.27 years with a M:F ratio of 1.81:1. The most common clinical variant of LP seen was oral LP (51%), with isolated nail involvement in 29%. Clinically, major features were onychorrhexis (92.3%), longitudinal melanonychia (74.3%), and nail bed erythema (54%). Histopathologically, hypergranulosis of nail matrix and bed epithelium (51.1%), followed by sawtooth acanthosis (44.4%) and lichenoid band (24.4%) were most common. A diagnosis using prevalent diagnostic criteria was confirmed in 51.1% biopsies. Distinctive "fraying of nail plate," a change not previously described, was noted in 33.3% cases.

CONCLUSION

Histopathology of nail LP has been attributed a diagnostic role; however, existing diagnostic criteria are not sensitive enough and need refinement. Not hitherto described features like fraying of nail plate are seen in a significant number of cases.

Uncovering subtle nail involvement in lichen planus with dermoscopy: a prospective, controlled study

Introduction

There are very few studies investigating the dermoscopic aspect of nail involvement in lichen planus and these studies described dermoscopic features of only clinically visible nail involvement in lichen planus.

Aim

To reveal subtle dermoscopic nail findings in patients with lichen planus.

Material and methods

The study included 40 patients with lichen planus and 40 healthy volunteers. All fingernails of the patients and healthy volunteers were examined by a handheld dermoscope and the findings detected were recorded. The patients were grouped by age, gender, disease duration and extent of the disease. The statistical analysis was performed using Chi square test.

Results

82.5% of the patients and 17.5% of the healthy volunteers showed at least one dermoscopic nail finding. The frequency of multiple splinter haemorrhage (p < 0.05), multiple leukonychia (p < 0.05), longitudinal erythronychia (p < 0.05), prominent hyponychial vascular structures (p < 0.05) and onycholysis (p < 0.05) observed in the patients group was statistically significant. The other findings included distal short longitudinal lines, onychorrhexis, solitary splinter haemorrhage and solitary punctate leukonychia and showed no statistically significant differences between the two groups.

Conclusions

To the best of our knowledge, this is the first study focusing on uncovering subtle nail involvement in lichen planus. The presence of dilated hyponychial vascular structures in lichen planus was first described in the present study. It can be concluded that the frequency of nail involvement in lichen planus is more than known. Dermoscopic imaging of the nails of all patients with lichen planus may help establish early diagnosis and treatment to avoid permanent nail damage.