Crusted (Norwegian) scabies: treatment of nail involvement

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.

Sarcoptes Infestation. What Is Already Known, and What Is New about Scabies at the Beginning of the Third Decade of the 21st Century?

Currently, there are three known subtypes of scabies: ordinary, crusted, and bullous. The worldwide prevalence of scabies remains high in the 21st century. To decrease the social, economic, and psychological impact on the enormous population infected, a lot of important work has been completed over the last 20 years concerning the management of scabies. For example, a standardization of guidelines for the treatment of scabies has been completed and programs have been designed for the prevention and treatment in endemic populations, called mass drug administrations. Unfortunately, these only apply to the ordinary form of scabies. Moreover, resistance to the drugs currently used in treatment is growing, which imposes the need to search for new treatments. For this purpose, new acaricides are being developed to enhance the therapeutic options for the patients' benefit and effectively treat this disease. There is also the necessity for prevention before the development of scabies. An effective vaccine has the potential to protect people before this disease, especially in endemic areas. Unfortunately, there are no such vaccines against Sarcoptes yet.

Subungual and ungual scabies: avoiding severe presentation in high-risk patients

Scabies is a pruritic disorder caused by Sarcoptes scabiei var. hominis infestation of the skin. Transferred by close body contact, scabies is endemic within nursing homes and among poor and overcrowded populations. Crusted scabies is a severe form of disease, characterised by a large, thick, crusted eruption with significant mite infestation. We report a patient hospitalised with crusted scabies that had massive nail involvement. A 79-year-old female patient with multiple comorbidities and several recent prior scabies diagnoses presented with agitation and dystrophic fingernails; scabies mites were found embedded in and below the nail keratin. Aggressive treatment resulted in complete resolution, with notable improvements in mental status. Crusted scabies with nail involvement is extremely rare and may be more likely to develop from initially subclinical infestation sites. It is important to consider this potential presentation, as standard topical treatments may prove ineffective when there is deep nail involvement.

[Scabies of the nail unit in an infant]

BACKGROUND

There are no guidelines regarding the management of scabies in infants and recurrence is common at this age. We report the case of an infant with subungual hyperkeratosis and ungual lesions subsequent to classic scabies.

PATIENTS AND METHODS

A 7-month-girl, treated 6 weeks earlier with esdepallethrin for scabies, consulted for acquired lesions on 3 toe nails. These nails were thickened and displayed subungual hyperkeratosis. Physical examination of the skin, the finger nails and mucous membranes was otherwise normal. Fungal analyses were negative, but direct microscopic examination revealed numerous larvae of Sarcoptes scabiei as well as ovular debris. The child was treated with urea 40% to obtain chemical avulsion of the nails, and with topical esdepallethrin and a quarter tablet of ivermectin orally; there was no follow-up of the child.

DISCUSSION

Ungual scabies has already been reported in crusted scabies and very rarely in classic scabies. Subungual and ungual locations of S. scabiei may constitute a source of reinfestation with scabies in infants. Treatment is not well defined and currently involves chemical avulsion of the nails and the application of topical antiscabies treatment.

Crusted scabies in association with human T-cell lymphotropic virus 1

BACKGROUND

Human T-cell lymphotropic virus I (HTLV- 1) infection can lead to myelopathy/tropical spastic paresis and adult T-cell leukemia/lymphoma (ATLL). Infection with HTLV-1 has also been associated with clinically significant immunosuppression. Crusted scabies, also known as Norwegian scabies, is an uncommon presentation of scabies that may occur in conjunction with immunosuppression. Although crusted scabies has been reported in association with HTLV-1 infection, to our knowledge it has never been described in association with HTLV-1 associated myelopathy.

OBJECTIVE

The aim is to describe a case of HTLV-1 associated myelopathy and concomitant crusted scabies.

METHODS

This article includes a case report and a literature review.

CONCLUSIONS

Crusted scabies is reported in association with HTLV-1 infection with or without concomitant ATLL. Crusted scabies should be considered in the differential diagnosis of a generalized cutaneous eruption in an HTLV-1 positive patient. Patients with crusted scabies from an HTLV-1 endemic population should be rested for a possible HTLV-1 infection. These patients may be at increased risk of progressing to ATLL.

Localized crusted scabies in the acquired immunodeficiency syndrome

Crusted scabies (CrS) is an uncommon occurrence among patients with AIDS. Indeed to date only five cases have been described, all with widespread lesions. A case of localized CrS appearing as a yellowish and crusted plaque on the second right toe is reported in a woman with AIDS. Scraping off the verrucous surface, as well as punch-biopsy revealed many mites within the horny layer. The infestation is related to the cutaneous immune response and thus CrS should be considered an opportunistic infestation in AIDS. The importance of the early diagnosis of CrS in order to prevent disseminated lesions and involvement of other health-care workers is underlined.

The spectrum of nail disease in patients with human immunodeficiency virus infection

There are no known pathognomonic nail signs of human immunodeficiency virus (HIV) infection. However, several presentations should increase the index of suspicion. (1) Proximal white subungual onychomycosis or superficial white onychomycosis, especially of the fingernails, is present. Trichophyton rubrum appears to cause both most commonly in HIV-infected patients. Periungual dermatophyte involvement and involvement of all 10 fingernails is unusual in non-HIV-infected persons. (2) Candida is a primary pathogen of the nail bed and nail plate especially if many nails are involved. (3) A destructive, almost granulomatous-like psoriatic involvement of the nails is present. (4) Squamous cell carcinoma of the nail bed in a young adult. There are no clinical trails to confirm the efficacy of therapy mentioned in this article. The treatment suggestions are empirical and are the personal views of the authors.