Periungual scabies in infants: a tough reservoir of mites presenting with lamellar desquamation

Ungual Scabies: A Case Report and Review of Literature

Introduction

Nail unit infestation by scabies mites (ungual scabies) is uncommon. It usually presents with distal subungual lesions, leading to recurrent and persistent disease by acting as a reservoir of infection. Periungual involvement in scabies with nail loss is rare and may lead to severe nail damage.

Case Presentation

We report a 14-year-old boy on chemotherapy for acute lymphocytic leukemia (ALL) who presented with extensive scaling and crusted plaques of scabies. Nail unit revealed periungual crusted plaques with paronychia and onychomadesis involving five digits. It was associated with partial to complete nail loss. Dermoscopy of periungual crusted plaques showed greyish-white scales with brown dots and globules. A sinuous burrow with a brown-triangular structure was visualized in the web space. KOH mount from skin scrapings showed the scabies mites. Treatment of scabies led to a marked improvement.

Conclusion

Though ungual scabies is generally a benign disease, proximal periungual involvement with damage to nail matrix is possible, leading to nail loss. We review manifestations of nail unit scabies reported in literature. Treatment options used and outcomes are also analyzed. The importance of nail-directed therapy in preventing relapses of scabies cannot be undermined.

Scabies: A Neglected Global Disease

BACKGROUND

Scabies is a skin disease caused by an obligate human parasite mite Sarcoptes scabiei var. hominis. Children under the age of two and elderly individuals are at the greatest risk. Knowledge of this condition is important for an early diagnosis to be made and treatment to be initiated.

OBJECTIVE

The review aimed to familiarize physicians with the clinical manifestations, diagnosis, evaluation, and management of scabies.

METHODS

A search was conducted using Pubmed with the built-in "Clinical Queries" tool. The search term "Scabies" was used. The categories of "epidemiology", "diagnosis", "therapy", "prevention" and "prognosis" had a limited scope for primary clinical studies. Meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews were included. Only papers published in the English language were included. A descriptive, narrative synthesis was provided of the retrieved articles.

RESULTS

Worldwide, scabies affects 200 to 300 million individuals annually. The average prevalence is estimated to be 5 to 10% in children of developing countries. Transmission usually occurs after close prolonged skin-to-skin contact. Classic scabies is characterized by an erythematous papular eruption, serpiginous burrows, and intense pruritus. Sites of predilection include the webs of the fingers, volar wrists, lateral aspects of fingers, extensor surfaces of elbows and knees, waist, navel, abdomen, buttocks, groins, and, genitals. A clinical diagnosis of classic scabies can be made on the basis of the history and clinical findings. Other clinical variants include crusted scabies, nodular scabies, and bullous scabies. Finding the mite, ova, or fecal pellets on microscopic examination of scrapings taken from skin lesions confirms the diagnosis of scabies infestation. For eradication of scabies mites, the drugs of choice are topical permethrin and oral ivermectin.

CONCLUSION

Scabies is a highly contagious parasitic cutaneous disease that is stigmatising and debilitating. Increased awareness, accurate diagnosis, and prompt treatment are essential for the effective control of scabies and for the prevention of the spread of the disease.