SUDANESE JOURNAL OF PAEDIATRICS

2021; Vol 21, Issue No. 2

CASE REPORT

Norwegian scabies in a child with Down syndrome

Dua Cebeci (1), Seide Karasel (2)

(1) Dermatology and Venereology Department, Famagusta State Hospital, Famagusta, Cyprus

(2) Physical Therapy and Rehabilitation Department, Famagusta State Hospital, Famagusta, Cyprus

Correspondence to:

Dua Cebeci

Famagusta State Hospital Dematology and Venerology Department, Famagusta, Cyprus

Email: perolidua [at] gmail.com

Received: 9 September 2020 | Accepted: 18 May 2021

How to cite this article:

Cebeci D, Karasel S. Norwegian scabies in a child with Down syndrome. Sudan J Paediatr. 2021;21(2): 215–218.

https://doi.org/10.24911/SJP.106-1599647837

ABSTRACT

Crusty scabies or Norwegian scabies is a highly contagious type of scab that is characterised by intense infestation by Sarcoptes scabiei in the skin and widespread, crusty, hyperkeratotic papules, plaques and nodules. The infection can be missed due to its atypical appearance. Patients with cognitive impairment or an immunodeficiency disorder (including immunosuppressive therapy) are prone to developing crusty scabies. Although the relationship between Down syndrome and crusted scabies is explained as an absence of effective immune system, it is still not fully understood. In this communication we report a 28-month-old girl with Down syndrome who presented with crusted scabies.

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KEYWORDS

Crusted scabies; cognitive impairment; Down syndrome.

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INTRODUCTION

Human scabies is an infestation caused by female mites (Sarcoptes scabiei hominis), which lay 40-50 eggs in their 4-6 weeks of life. Norwegian scabies was described by Danielssen and Boeck as a scabies infestation caused by millions of mites in patients with leprosy in Norway [1].

It is highly contagious and severe form of scabies characterised by profuse proliferation of mites. Itching is usually not an obvious symptom, and therefore the diagnosis may be missed. Occurrence in healthy infants has rarely been reported. Generally, it affects paediatric patients with impaired cell-mediated immunity such as Down syndrome, congenital T cell deficiency, chronic mucocutaneous candidiasis, kwashiorkor, dystrophic epidermolysis bullosa and those receiving systemic or topical corticosteroids [2]. This rare variant of scabies can easily mimic other dermatologic disorders, such as psoriasis, eczema, seborrheic dermatitis, Darier’s disease, pityriasis rubra pilaris, lichen planus and cutaneous lymphoma [3]. We present and discuss an immunocompetent Down syndrome child with crusted scabies whom we treated successfully with a combination of permethrin and topical scabicides, keratolytics and emollients.

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CASE REPORT

A 28-month-old female child, a known case of Down syndrome and affected by atopic dermatitis since birth, presented with the complaints of itchy scaly lesions predominantly over her hands and feet for the past 4 months. In the last 2 weeks a worsening in the cutaneous xerosis and erythema was reported and topical treatment with clobetasol propionate was started to decrease atopic lesion. Her family members also had a similar complaint but with less severity. Dermatological examination revealed diffuse, crusted, hyperkeratotic, and erythematous patches and plaques, involving the trunk and intensely pruritic hyperkeratotic crusted scaly plaques over bilateral hands and feet (Figure 1).

Some of the lesions were excoriated. Finger nails showed dystrophic changes and subungual hyperkeratosis. Past medical history revealed that the baby was born from a 36-year-old primigravida woman at 39 weeks of gestation following an uncomplicated pregnancy. She had undergone an operation due to the endocardial cushion defect and her routine paediatric cardiology follow-ups were still continuing. The diagnosis of was confirmed by dermoscopy examination pressing on the lesion and observing numerous scabies tunnels (Figure 2).

A diagnosis of crusted scabies was made (Figure 3).

The other routine investigations were within the normal limits. The patient was treated with topical treatment for 3 days, with a mixture of 95 g of vaseline and 5 g precipitated sulphur and in 4th day with topical permethrin. She is on follow-up and is lesion free. Her family members were also treated for scabies.

Figure 1. Diffuse, crusted, hyperkeratotic and erythematous patches and plaques, involving the trunk and intensely pruritic hyperkeratotic crusts on the fingers, palms and feet in a Down syndrome child with crusted scabies.

Figure 2. Dermoscopy examination pressing on the crusted lesion and observing numerous scabies tunnels.

Figure 3. Photomicrograph of an adult S. scabiei mite on potassium hydroxide mounts (×10).

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DISCUSSION

It has been shown in studies that the risk of developing crusted scabies infestation is increased in immunocompromised patients. Patients with cognitive or physical disabilities such as Down syndrome are one of them [4]. Two mechanisms related to this issue are discussed; first theory is that the cognitive delay can decrease the ability to interpret itching and the other theory is based on immune system abnormalities, including mild to moderate T and B cell lymphopenia and impaired mitogen-induced T cell proliferation [5]. Our patient is similar in terms of having Down syndrome as a predisposing factor and suppressing immunity due to the cardiac therapies she received. She had lesions characteristic of scaly, crusty and scaly scab 4 months before being treated with topical corticosteroids as a case of atopic dermatitis. Therefore, this case emphasises that if the lesions are crusted and hyperkeratotic, especially if the lesions do not respond to steroid therapy, crusted scabies should be considered in the differential diagnosis of atopic dermatitis. The distinctive clinical sign of this scabies variety is thick crust. Other classical clinical features such as papules, excoriations may be absent. These findings are due to the high concentration of mites that trigger the exaggerated keratin formation in the stratum corneum [6]. Diagnosis can be confirmed by clinical and dermoscopic examination or a rapid bedside test, which involves visualisation of mites, eggs, or faces from skin scrapings analysed directly under a microscope [7]. Complications of infestation include impetigo, ecthyma, cellulitis, lymphangitis, sepsis and superinfection with nephritogenic strains of Streptococcus pyogenes leading to glomerulonephritis. Therefore, the early treatment it is necessary to protect these patients with weak immune systems from these life-threatening complications [8].

Up until now, treatment guidelines have not been fully established, but the recommended management based on case series is a combination of topical and oral agents. Scabicides such as 5% permethrin cream and keratolytics (e.g. urea) are effective as topical medications. Oral ivermectin is used in a 5-dose regimen with doses of 200 μg per kg on days 1,2,8,9 and 15; and in severe cases, two additional doses are given on days 22 and 29 [6].

Mechanical debridement of mites and eggs by scraping is an effective measure that may be important to limit proliferation in patients with cognitive impairment, physical disability or neuropathy. Also, keeping in mind that this disease is contagious, an important part of management includes room isolation, protective clothing, continuous cleaning of personal items and minimising contact with healthcare worker, thereby reducing the risk of institutional outbreaks [7]. Since delay in diagnosis and treatment can lead to the spread of infestation, physicians should be careful about scabies in children if their immunity is weakened or insufficient [1].

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CONCLUSION

Crusted scabies or Norwegian Scabies is a rare but highly contagious disease caused by scabies mites. People with low immunity, (including those with human immunodeficiency virus infection, lymphoma or other conditions), or cognitive impairment such Down syndrome may develop this disease.

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CONFLICTS OF INTERESTS

The authors declare that there are no conflicts of interest regarding the publication of this paper.

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FUNDING

None.

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ETHICAL APPROVAL

Informed written consent was obtained from the parents of this child for clinical photographs and publication of medical details. Confidentiality of patient’s data was ensured at all stages. Ethics committee approval was also obtained from our institute.

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