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ORIGINAL ARTICLE
Year : 2019  |  Volume : 20  |  Issue : 1  |  Page : 46-51

Dermoscopic study of scabies in children


1 Department of Dermatology Venereology and Leprosy, Navodaya Medical College Hospital and Research Centre, Raichur, Karnataka, India
2 Dr. Srinivasa Murthy's Skin and Cosmetology Centre, Bangalore, Karnataka, India
3 Sambharam Institute of Medical Sciences, Kolar, Karnataka, India

Date of Web Publication14-Dec-2018

Correspondence Address:
Dr. Shilpitha Srinivas
Room No. 39, Department of Dermatology Venereology and Leprosy, Navodaya Medical College Hospital and Research Centre, Mantralayam Road, Raichur - 584 103, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijpd.IJPD_25_18

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  Abstract 


Background: Dermoscopy is a technique involving the rapid and magnified observation of the skin. Infection with Sarcoptes scabiei in children usually presents with pruritus. Primary scabetic lesions consist of small, erythematous papules, and burrows. The definitive diagnosis of scabies is by visualizing the mites, eggs, or feces under the microscope. Aims and Objectives: The aim of the study was to compare the diagnosis of scabies in children with naked eye examination and a dermoscope. The objective was to find out if there was a significant difference between the two methods of diagnosis of scabies. Subjects and Methods: A cross-sectional study was done. Fifty children aged between 1–15 years with symptoms clinically suspicious of scabies from May 15, 2016 to May 14, 2017 were taken. Thirty were male and 20 were female. After taking history, the lesions were examined clinically and with Dermalite DL4 and photographs were taken. A triangular structure with a furrowing burrow was considered to indicate the presence of a mite. Results: Among 50 children, 37 children had clinical features of scabies: the presence of burrows and scabetic nodules. Among 50, 45 children had dermoscopic features of scabies: the presence of the delta glider sign. The data were analyzed using Z- test using MS Excel 2010. There was a significant difference (P < 0.03) on comparing the number of children diagnosed with scabies with naked eye and dermoscopic examination. Conclusion: A handheld dermoscope can be a useful tool to rapidly and non invasively diagnose scabies with high sensitivity compared to Clinical Examination.

Keywords: Delta glider sig, dermoscopy, scabies


How to cite this article:
Srinivas S, Herakal KC, Murthy SK, Suryanarayan S. Dermoscopic study of scabies in children. Indian J Paediatr Dermatol 2019;20:46-51

How to cite this URL:
Srinivas S, Herakal KC, Murthy SK, Suryanarayan S. Dermoscopic study of scabies in children. Indian J Paediatr Dermatol [serial online] 2019 [cited 2019 Mar 22];20:46-51. Available from: http://www.ijpd.in/text.asp?2019/20/1/46/247549




  Introduction Top


Scabies is a contagious skin disease caused by the infestation of sarcoptei scabei var.hominis. Overcrowding is an important factor in the transmission of scabies. In developing countries, scabies is commonly seen in the preschool children and adolescents and it decreases in mid-adulthood and increases in the elderly.[1] For many years, ex vivo skin scrapings were used for the diagnosis of scabies. Recently, dermoscopy has been used for the in vivo diagnosis of scabies. As scraping the skin can cause trauma and anxiety to the child, dermoscopy is an effective and noninvasive method to diagnose scabies.


  Subjects and Methods Top


A cross-sectional study was done. The study was approved by the Ethics Committee and Institutional Review Board. Informed consent was obtained from all participants at study entry. Fifty children aged between 1 and 15 years with symptoms clinically suspicious of scabies coming to the OPD from May 15, 2016, to May 14, 2017, were taken. Thirty males and 20 females were taken. The aim of the study was to compare the number of children diagnosed with scabies on naked eye examination alone and on dermoscopic examination after selecting children with history suggestive of scabies. The objective of the study was to find out if there was a significant difference between the two methods of diagnosis of scabies.

History and clinical examination were done, and the data were recorded. Informed consent was taken from the parents. Out of 50 children, 40 had been given treatment for pruritus. Children had symptoms of nocturnal itching from 1 week to 3 months.

Inclusion criteria

  • Children aged between 1 and 15 years irrespective of whether treatment was given to them or not
  • The classical sites of involvement of scabies, visible burrows, scabetic nodules, or family history of scabies were included in the study.


Exclusion criteria

  • Children who were not cooperative for dermoscopic examination.


Clinical examination

Children were examined at seven common sites of involvement of scabies: Web spaces, flexural aspect of wrists and elbows, axillae, umbilicus, buttocks, and genitalia for the presence of burrows. Burrows are seen as a wavy, scaly gray line on the skin surface.[2] Apart from burrows, infestation with scabies also presents with papules, vesicles, pustules, and nodules in the affected sites. If the above clinical features were seen in the children, they were diagnosed as having scabies.

Dermoscopy

The lesions were examined a dermoscope at seven topographic areas where the mite was suspected. If the parents noticed less than seven sites, all the sites were examined with the help of a dermoscope. If more than seven sites were reported by the parent, seven sites were chosen and were examined using a dermoscope. The dermoscopic examination was done with Dermalite DL4 ×10 magnification [Figure 1]. Application of a liquid interface was not done in all cases as it was not required in every case. Photographs were taken with Canon IXUS 133. A triangular structure with a furrowing burrow was considered to indicate the presence of a mite. This is also called as a contrail, jetliner with its trail, or delta glider sign.[3] Even the burrow filled with eggs is another diagnostic feature. This is only seen with the use of a videodermoscopy which uses a higher power magnification and was not seen in our study.
Figure 1: Dermalite DL4

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Statistical analysis used

The data were numerical data and were analyzed using Z test using MS Excel 2010.


  Results Top


Fifty children aged between 1 and 15 years with symptoms clinically suspicious of scabies coming to the OPD from May 15, 2016, to May 14, 2017, were taken. Thirty males and 20 females were taken. In 30 male children, 14% (7) were aged between 1 and 5 years, 30% (15) were between 5 and 10 years, and 16% (8) were between 10 and 15 years [Table 1] and [Table 2]. Among 20 female children, 8% (4) aged between 1 and 5 years, 22% (11) between 5 and 10 years, and 1% (five) who were aged between 10 and 15 years. After taking history, it was seen that among 50 children, 16 males (32%) and ten females (20%) had family history of contagiousness [Table 3]. Twenty-two males (44%) and 11 females (22%) had H/O pruritus with nocturnal exacerbation [Table 4]. On naked eye examination after taking of history, out of the 30 males, 22 males (44%) and out of 20 females, 15 (30%) could be diagnosed as having scabies [Table 5]. On dermoscopic examination, out of 30 males 28 (56%) and out of 20 females, 17 (34%) were diagnosed definitely as having scabies [Table 6]. Dermoscopy of the web spaces of a 13-year-old boy in polarized light showing burrow [Figure 2].
Table 1: Age and sex distribution of cases

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Table 2: Age and sex distribution chart

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Table 3: Family history of contagiousness

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Table 4: History of pruritus with nocturnal exacerbation

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Table 5: Clinical history and naked eye examination

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Table 6: Clinical history and dermoscopic examination

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Figure 2: Dermoscopy of the web spaces of a 13-year-old boy, magnified image. Polarized light mode used. Arrow showing mite

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Using the Z-test, the one-tailed probability value of P was obtained. The P value calculated for the diagnosis of scabies using only clinical history and examination was 0.0001. The P value calculated using clinical history and dermoscopy was 0.02. On comparison of the total number of patients diagnosed with scabies using clinical examination (37) and dermoscopic examination (45) using Z-test, a P = 0.03 was obtained [Table 7]. This indicates that a significant difference exists between the two results. On comparison of the number of male children diagnosed with scabies using clinical examination (22) and dermoscopic Examination (28), P = 0.03 [Table 7]. On comparison of the number of female children diagnosed with scabies using clinical examination (15) and dermoscopic examination (17), P = 0.42 was obtained [Table 7]. Thus, this P = 0.03 was significant, and the P = 0.42 was not statistically significant.
Table 7: Comparison of clinical examination and dermoscopic findings

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Among the seven sites dermoscopically examined, the web spaces and axillae were the most common sites in which the mite could be visualized. Dermoscopy of the web spaces of a 2-year-old boy [Figure 3] and [Figure 4]. Clinical examination of the 2-year-old boy showing erythematous papules on the dorsum and web spaces of the hands [Figure 5] and [Figure 6]. In the 45 children diagnosed with scabies using a dermoscope, 38 children had web space involvement, 32 had axillae involvement. Twenty-seven and 25 children had flexural aspect of wrists and elbows involvement, respectively. Twenty three, 25 and 13 children had umbilicus, genitalia and buttocks involvement, respectively [Table 8], [Table 9], [Table 10], [Table 11], [Table 12], [Table 13], [Table 14]. Dermoscopy of the flexural aspects of the wrists of a 10-year-old girl in polarized light showing burrow [Figure 7] and [Figure 8]. Dermoscopy of the web spaces of a 10-year-old boy in polarized light showing burrow [Figure 9] and [Figure 10].
Figure 3: Dermoscopy of the web spaces of a 2-year-old boy in polarized light. Arrow showing burrow

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Figure 4: Dermoscopy of web spaces of a 2-year-old boy in polarized light under magnification. Arrow showing burrow

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Figure 5: Hands of a 2-year-old boy suspected of scabies

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Figure 6: Erythematous papules on the dorsum and the web spaces of the hands of a 2-year-old boy

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Table 8: Most common sites of positive dermoscopicfindings: Web spaces

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Table 9: Axillae

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Table 10: Flexural aspect of the wrists

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Table 11: Flexura l aspect of the elbows

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Table 12: Umbilicus

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Table 13: Genitalia

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Table 14: Buttocks

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Figure 7: Dermoscopy of the flexural aspect of wrist of a 10-year-old girl. Polarized light mode used. 40x magnification. Arrow showing burrow

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Figure 8: Dermoscopy of the Flexural aspect of wrist of a 10yr- yr- old girl. Polarised light mode was used. 10x magnification. Arrow showing burrow

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Figure 9: Dermoscopy showing a burrow in the web spaces of a 10-year-old boy. Polarized light mode used. Arrow showing burrow with mite

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Figure 10: Dermoscopy showing a burrow in the web spaces of a 10-year-old boy, magnified image. Polarized light mode used. Arrow showing burrow with mite

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  Discussion Top


The female mite is around 0.2–0.4 mm long and burrows into the stratum corneum to lay its eggs. Burrows are often in an s shape or z shape. The life cycle of the scabies mite is for around 30 days. Infection is spread by close skin to skin contact. It makes a 0.5–5 mm burrow every day, and it survives on dissolved skin and does not feed on blood. It is estimated only 10% of the eggs mature into adults. There are estimates that over 300 million people worldwide are affected with scabies.[4] Classical scabies affects the anterior axillary folds, nipple area, periumbilical skin, elbows, volar surface of the wrists, interdigital webspaces, thighs, buttocks, penis, scrotum, and ankles.[5] This is referred to as the circle of Hebra. Identification of the burrow can be done with the help of a black felt tip marker applied to the burrow.[4] Diagnosis of scabies invasively is by skin scrapings. After scraping the skin, the sample is suspended in mineral oil or saline. The presence of the mite or egg casings under microscopy is considered to be the diagnostic criteria. As the specimen debris can look like the scybala, it alone is not considered diagnostic. Often while handling and processing, the skin scrapings errors can occur. Scabies affects all socioeconomic classes with women and children being disproportionately affected. Among adults, sexual transmission is probably the most important route of transmission. Crusted scabies is a severe variant of scabies and is characterized by the presence of severe hyperkeratotic lesions seen in the immunocompromised host.[6] It is characterized by the absence or presence of only minimal itching.[7] Scabies is caused by prolonged close personal contact and transmission through fomites is more common in crusted scabies.[7] Pruritus with nocturnal exacerbation is the main symptom. Diagnosing scabies in infants, elderly or in patients on prolonged immunosuppressive therapy could be a challenge as they lack the typical clinical features.[8] Scabies in infants affects the face, palms, soles, head, neck, and scalp. Neonatal scabies is a different subset of scabies with atypical presentations.[9] Lesions can be in the form of papules, pustules, and vesicles.[10] Crusting and secondary bacterial infection of involved skin are commonly seen. Nocturnal Pruritus is absent. As burrows are rarely seen, neonates were not included in this study. In developing countries, scabies is associated with considerable morbidity including secondary infection, abscess, lymphadenopathy, and poststreptococcal glomerulonephritis.[11] Scabies is a common infestation seen in preschool children.[12] Scabies in children can mimic other itchy skin disorders such as papular urticaria and atopic dermatitis and accurate diagnosis is needed to give effective treatment.

Dermoscopy was initially used for the diagnosis of skin tumors. Nowadays, it has gained popularity in the use of infectious and inflammatory skin disorders. Thus, it has been found to be of good use in the daily practice of the dermatologist.[13] A dermoscope can be considered as the dermatologist's stethoscope.[14] A pocket handheld dermoscope is portable, painless and is easy to use. Dermoscope is useful in a tertiary care center. It is also useful for diagnosing scabies in the field, in the endemic or epidemic context. It is less time-consuming and is more acceptable to patients than skin scrapings. It can be used to replace skin scrapings as it allows a quick screening of a large number of sites. Apart from that, it can also be used in therapeutic trials to select the site in patients where skin scrapings can be done. In a study done by Dupuy et al., sensitivity for the diagnosis of scabies (91%) using dermoscopy was higher than the microscopic examination for the diagnosis of scabies (90%).[15] A handheld dermoscope has been shown to have high sensitivity even in unexperienced hands.[15] It can also help to make treatment decisions. High cost of the dermoscope is a disadvantage. Dermoscopy has been found to be useful for the diagnosis of Incognito scabies.[16] To avoid an invasive test-like skin scrapings, even adhesive tape test to diagnose scabies has been done in resource poor settings.[17]

Jetliner sign is seen as a triangular structure which corresponds to the anterior section of the mite including the mouth part and the two pairs of the front legs.[6] It has also been called as spermatozoid. Sometimes, traditional methods of diagnosis of scabies can be missed due to the absence of skin signs as the reaction to the mite can be less pronounced. This is when dermoscopy has been found to be useful. Apart from dermoscopy, videodermoscopy, reflectance confocal microscopy, and optical coherence tomography are other newer, noninvasive methods that can be used for the diagnosis of scabies.[18]

This study was done as not many studies have been done to study the dermoscopic features of scabies in children. In this study, it was seen that on history and clinical examination alone, the number of children diagnosed as scabies was less compared to history and dermoscopic examination. This is useful in a resource-poor setting where microscopic examination of the skin scrapings may not be possible due to the unavailability of microscopes. In such a clinical setting, the pocket handheld dermoscope is portable, and the dermoscopic examination of the patients can be rapidly done. The success rates are higher than clinical examination with the naked eye. A statistical significant difference was seen in the number of children diagnosed with scabies on comparing the clinical examination versus dermoscopic examination (P 0.03). Also as more number of males were included in the study compared to females, the number of males diagnosed with scabies was more in both clinical examination (22) and dermoscopic examination (28) compared to the number of females in clinical examination (15) and dermoscopic examination (17). Thus, on comparing the two noninvasive techniques, dermoscopic examination was more sensitive than only clinical examination of children in the diagnosis of scabies.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Acknowledgments

We would like to express our sincere gratitude to Dr. Girianna Gowda for help with the statistics and Dr. Sweta Prabu for her inputs and suggestions.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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Stone PS, Goldfarb JN, Bacelieri RE. Scabies, other mites, and pediculosis. In: Wolff K, Goldsmith LA, Katz IS, Gilcherset AB, Paller AS, Leffell DJ, editors. Fitzpatrick's Dermatology in General Medicine. 7th ed. USA: McGraw Hill Companies; 2008. p. 2029-32.  Back to cited text no. 4
    
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Chandrashekar BS, Mukherjee SS. An unusual guest in the panel of differentials! Indian J Paediatr Dermatol 2016;17:62-4.  Back to cited text no. 9
    
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Singhal AK, Kushwah R, Yadav D, Jain S. A case report of neonatal scabies. Indian J Paediatr Dermatol 2017;18:104-6.  Back to cited text no. 10
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Feldmeier H, Jackson A, Ariza L, Calheiros CM, Soares Vde L, Oliveira FA, et al. The epidemiology of scabies in an impoverished community in rural Brazil: Presence and severity of disease are associated with poor living conditions and illiteracy. J Am Acad Dermatol 2009;60:436-43.  Back to cited text no. 11
    
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Bisht JS, Rana SK, Kumari N, Aggarwal B, Mehta A, Singh R. Pattern of dermatoses in preschool children in a teaching hospital in Uttarkhand, India. Indian J Paediatr Dermatol 2015;16:198-202.  Back to cited text no. 12
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Lallas A, Zalaudek I, Argenziano G, Longo C, Moscarella E, Di Lernia V, et al. Dermoscopy in general dermatology. Dermatol Clin 2013;31:679-94, x.  Back to cited text no. 13
    
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Dupuy A, Dehen L, Bourrat E, Lacroix C, Benderdouche M, Dubertret L, et al. Accuracy of standard dermoscopy for diagnosing scabies. J Am Acad Dermatol 2007;56:53-62.  Back to cited text no. 15
    
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Walter B, Heukelbach J, Fengler G, Worth C, Hengge U, Feldmeier H, et al. Comparison of dermoscopy, skin scraping, and the adhesive tape test for the diagnosis of scabies in a resource-poor setting. Arch Dermatol 2011;147:468-73.  Back to cited text no. 17
    
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Micali G, Lacarrubba F, Verzì AE, Chosidow O, Schwartz RA. Scabies: Advances in noninvasive diagnosis. PLoS Negl Trop Dis 2016;10:e0004691.  Back to cited text no. 18
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11], [Table 12], [Table 13], [Table 14]



 

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