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ORIGINAL ARTICLE
Year : 2021  |  Volume : 22  |  Issue : 3  |  Page : 215-219

Pediatric dermatophytosis of the skin: current clinico epidemiological and antifungal susceptibility patterns in a tertiary care rural hospital


1 Department of Dermatology, Raja Rajeswari Medical College and Hospital, Bengaluru, Karnataka, India
2 Department of Microbiology, Raja Rajeswari Medical College and Hospital, Bengaluru, Karnataka, India

Date of Submission27-May-2020
Date of Decision14-Jul-2020
Date of Acceptance30-Mar-2021
Date of Web Publication30-Jun-2021

Correspondence Address:
Yadalla Kumar Kishan
70, Padma Nivasa, 3rd Cross, MG Ext. HV Halli, Raja Rajeswari Nagar, Bengaluru - 560 098, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijpd.IJPD_92_20

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  Abstract 


Background: Dermatophytosis is a common infection seen in tropical countries like India. With the onset of the 21st century, cases of antifungal resistance in dermatophytoses began to emerge as a therapeutic challenge. While tinea capitis, the predominant presentation in pediatric age group, has been extensively studied, the current scientific literature lacks in articles that assess the antifungal susceptibility patterns in pediatric dermatophytosis particularly involving the skin. Objective: This study attempts to identify and assess the changing clinico-epidemiological trends in the profile of pediatric dermatophytosis involving the skin, and its antifungal susceptibility patterns. Materials and Methods: Thirty subjects of 0–18 years of age with clinically diagnosed dermatophytosis were evaluated with history, examination and followed by a potassium hydroxide wet mount. Skin scrapings were also taken for fungal culture and antifungal susceptibility test against 10 commonly used antifungal agents using Broth Microdilution method as per Clinical and Laboratory Standards Institute (CLSI) M38-A2 guidelines. Results: Trichophyton rubrum was the most common dermatophyte isolated. Recurrent dermatophytosis was seen in 20% subjects. Tinea corporis was the predominant presentation. Steroid-modified Tinea was observed in 33.33% cases. Based on in vitro antifungal susceptibility testing, terbinafine and luliconazole were found to be the most effective systemic and topical agents, respectively. Conclusion: The rampant use of over-the-counter medications containing topical steroids is a rising issue in the treatment of both adult and pediatric dermatophytosis. Education and counseling of patients are very important for correct treatment of the condition and also to prevent the rise of recurrent infections.

Keywords: Antifungal susceptibility, pediatric dermatophytosis, tinea incognito


How to cite this article:
Kashyap P, Kishan YK, Prakash R. Pediatric dermatophytosis of the skin: current clinico epidemiological and antifungal susceptibility patterns in a tertiary care rural hospital. Indian J Paediatr Dermatol 2021;22:215-9

How to cite this URL:
Kashyap P, Kishan YK, Prakash R. Pediatric dermatophytosis of the skin: current clinico epidemiological and antifungal susceptibility patterns in a tertiary care rural hospital. Indian J Paediatr Dermatol [serial online] 2021 [cited 2021 Aug 5];22:215-9. Available from: https://www.ijpd.in/text.asp?2021/22/3/215/319955




  Introduction Top


India is a tropical country where superficial fungal infections are highly prevalent.

Dermatophytes are keratinophilic filamentous fungi capable of causing chronic infections of hair, nails and skin.[1] Infection of keratinized tissue caused by these fungi is called dermatophytosis, which is among the most common public health problems in hot and humid tropical countries like India.[2] This mundane infection is now ushering into an era of resistance. There has also been a rise in the prevalence of dermatophyte infections among the pediatric age group. It is especially common among children aged 3–9 years, particularly among those, who live in crowded conditions in urban areas.[3]

Despite anti-mycotic drug resistance emerging as a serious issue in India, specific data on this subject in the clinical scenario is limited. Although there are articles that address the antifungal susceptibility patterns in Tinea capitis in children,[4] the current scientific literature lacks studies that assess the patterns of antifungal susceptibility in pediatric tinea corporis, which is caused by very different groups of dermatophytes comparatively.

This study attempts to identify and assess the changing clinico-epidemiological trends in the profile of pediatric dermatophytosis involving the skin, and its antifungal susceptibility patterns.


  Materials and Methods Top


This was a hospital-based cross-sectional study conducted over 3 months, at a tertiary care rural center in Karnataka, India. After acquiring institutional ethics committee permission XXMCH-IEC/34/2018-19 letter dated October 28, 2017 and informed written consent from the parent/guardian, each subject was evaluated with detailed history and physical examination. The study included 30 subjects aged between 0+ and 18 years and any gender with clinically diagnosed dermatophytosis involving the skin fulfilling the inclusion criteria of pediatric dermatophytosis of skin and excluding tinea capitis and patients unwilling to participate in the study.

A semi-structured questionnaire was used to collect relevant information, followed by collection of skin scrapings for wet mount using 10% potassium hydroxide (KOH) to look for refractile filamentous hyphae [Figure 1]. Irrespective of positive or negative direct microscopy results, fungal culture was done on Sabouraud's Dextrose Agar. The species were identified based on the morphological features of the culture colonies, hyphal structures, and micro-/macro conidia using lactophenol cotton blue stain [Figure 2].
Figure 1: Potassium hydroxide mount showing filamentous hyphae of dermatophytes (×40)

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Figure 2: Lactophenol cotton blue stain showing hyphae and conidia of Trichophyton rubrum (×40)

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Anti-fungal sensitivity testing (AFST) was done by broth microdilution method (MD) as per CLSI M38-A2 guidelines to find the Minimum Inhibitory Concentration (MIC) of each drug for the test fungal isolates.[5] Susceptibility of dermatophytes to 10 commonly prescribed anti-fungal drugs were tested, which included systemic drugs such as Terbinafine, Itraconazole, Voriconazole, Griseofulvin and Fluconazole; and topical drugs such as Ketoconazole, Luliconazole, Sertaconazole, Clotrimazole, and Miconazole.

Anti-fungal agent stock solutions were prepared in Dimethyl Sulfoxide (Sigma Aldrich), except Fluconazole which was prepared in distilled water. The stock solutions were stored in sterile tubes at −70°C. The drug concentrations tested were 0.001–0.5 μg/ml for itraconazole and terbinafine, 0.125–64 μg/ml for griseofulvin and fluconazole, 0.016–16 μg/ml for luliconazole and 0.0313–16 μg/ml for voriconazole, ketoconazole, sertaconazole, clotrimazole, and miconazole.[6],[7],[8]

To prepare the fungal inoculum, isolates were subcultured on Corn Meal Agar slants for 1 week at 35°C to produce conidia. Sterile normal saline was added to the agar slant, and the cultures were gently swabbed with a cotton-tipped applicator to dislodge the conidia from the hyphal mat. The suspension was transferred to a sterile tube, and the volume was adjusted to 10 ml with sterile normal saline and centrifuged at 3000 rpm for 5 min. The resulting supernatant adjusted to 0.5 McFarland standard was diluted in Roswell Park Memorial Institute (RPMI) 1640 medium (Sigma Aldrich) to the desired concentration.

Sterile round-bottomed 96-well microdilution plates were set up in accordance with the CLSI M38-A reference method [Figure 3]. The drug stock solutions were diluted in RPMI in twice the final concentration followed by the addition of an equal volume of the pre-adjusted inoculum of dermatophyte isolates. Columns 1 through 10 were filled with 100 μl of the inoculum and 100 μl of the serially diluted antifungal agent. Column 11 was filled with 100 μl of the inoculum and 100 μl of media that served as a growth control. Column 12 was filled with 200 μl of RPMI medium to serve as a sterility control. Trichophyton rubrum ATCC 1546 and Candida parapsilosis ATCC strains were used for quality control. The MD plates were incubated at 35°C for 4 days or until sufficient growth (i.e., confluent hyphal growth covering the bottom of the well) was observed in the control wells containing media without antifungal drugs.
Figure 3: Microtiter plates set up as per CLSI 38 A2 guidelines

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The MIC was defined as the concentration of drug at which the growth of the organism was inhibited up to 80% compared with the growth in the control well.[9] All isolates were run in duplicate, and the results were read visually. MIC50 and MIC90 are defined as the drug concentration that can inhibit the growth of 50% and 90% isolates respectively.

Data analysis

Data analysis was done using SPSS software version 11.0 (SPSS Inc., Chicago, IL, USA). Results on quantitative data were presented as mean ± standard deviation and results on qualitative data were presented in terms of frequency and percentages. Descriptive tables and graphs were used for pictorial representation of descriptive data.


  Results Top


[Table 1] depicts the clinico-epidemiological findings in our study.
Table 1: Clinico-epidemiological findings of dermatophytosis in this study

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Tinea corporis was the most common clinical presentation [Figure 4] followed by tinea incognito [Figure 5].
Figure 4: Tinea corporis in an infant

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Figure 5: Tinea incognito in a child

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The in vitro sensitivity profile of 10 commercially available antifungal agents against 12 dermatophyte isolates belonging to 2 commonly prevalent species was evaluated using broth MD. The MIC range, MIC50, MIC90, and geometric mean (GM) of MIC of each drug were calculated for every dermatophyte species.

[Table 2] shows the overall MIC range, MIC50, MIC90, and GM of MIC of the antifungal agents tested.
Table 2: Minimum inhibitory concentration range, minimum inhibitory concentration50, minimum inhibitory concentration90 and geometric mean of minimum inhibitory concentration of the antifungal agents tested

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Based on the calculation of MIC values, terbinafine, followed closely by Itraconazole SHOWED the highest efficacy among the systemic agents, while luliconazole was the most efficient topical drug. Fluconazole was the least effective drug in general. However, none of the agents exhibited in vitro antifungal resistance.

The GMs of all the drugs except luliconazole against Trichophyton mentagrophytes were higher than that for T. rubrum . This implies that all the antifungal agents tested were more efficacious against T. rubrum isolates as compared to T. mentagrophytes. Luliconazole was equally effective in both groups of dermatophyte isolates [Figure 6].
Figure 6: Comparison between the geometric means of minimum inhibitory concentration of the antifungal agents in Trichophyton rubrum and Trichophyton mentagrophyte. ITZ - Itraconazole; TBF- Terbinafine; VCZ – Voriconazole; FCZ – Fluconazole; GSV – Griseofulvin; SCZ – Sertaconazole; KTZ – Ketoconazole; MCZ – Miconazole; CTZ - Clotrimazole; LCZ - Luliconazole

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  Discussion Top


Dermatophytosis is a common menace in tropical countries like India. Our study attempted to assess the changing clinico-epidemiological trends in pediatric dermatophytosis involving skin, including the prevalence of steroid-modified dermatophytosis and its antifungal susceptibility patterns. Similar to prior studies, males were affected more than females in our study, with a majority of the subjects from lower socioeconomic background and 60% cases having a history of contact with an infected family member.[3]

20% of our subjects gave a history of recurrent dermatophytosis affecting the skin, while 33.33% gave a history of using over-the-counter topical formulations containing corticosteroids in the preceding 4 weeks. This fact points to the prevalence of recurrent dermatophytosis and steroid-modified tinea in the rural population where this study was conducted owing to illiteracy, overcrowding, and lack of personal hygiene. Tinea incognito was seen in 33.33% cases, while Tinea corporis was the predominant clinical presentation (40%).

76.67% samples were positive for filamentous hyphae under KOH mount, which is approximately similar to the KOH positivity in the study by Mishra et al. However, contrary to their observation where the predominant species isolated was T. mentagrophytes, the most common dermatophyte isolated in this study was T. rubrum, followed by T. mentagrophytes.[10]

Based on AFST, Terbinafine showed the highest efficacy amongst the systemic agents, followed very closely by Itraconazole, while Luliconazole was the most efficient topical drug. Fluconazole was the least effective drug in general. However, none of the agents exhibited in vitro antifungal resistance. Based on the GMs and range of MICs, T. rubrum isolates showed higher susceptibility to all the antifungal agents as compared to T. mentagrophytes.

Despite an extensive online search, we could not find any relevant article studying the antifungal susceptibility patterns in dermatophytosis of the skin in the pediatric age group to compare our findings with.


  Conclusion Top


To the best of our knowledge, this is the only study from Southern India evaluating the antifungal susceptibility patterns to most commonly prescribed drugs seen in pediatric dermatophytosis involving the skin. The susceptibility pattern of dermatophytes varies from species to species, which is why it is important to determine the fungal isolate especially in cases of recalcitrant dermatophytosis. We observed a high rate of use of topical over-the-counter medications in children. Hence, education and counseling the parents regarding such practices are very important. Although recurrences may also be due to re-infection from affected family members or the environment, it is more likely that the duration of antifungal therapy prescribed may be inadequate. Extending the therapy for at least 2–3 weeks after symptomatic relief should be advised along with appropriate treatment of any infected close contacts and patient counseling regarding behavioral and lifestyle modifications. Limitations of the study - This study does not correlate the antifungal susceptibility patterns with clinical outcomes. Further large-scale studies from other geographical regions would warrant a clearer picture of both the clinicomycological as well as antifungal susceptibility patterns in the global pediatric population. The susceptibility patterns of eberconazole, oxiconazole, and fenticonazole could not be tested in this study due to constraints in acquiring raw materials for AFST. The results of broth microdilution in our study were read visually, which can lead to subjective errors. Future studies should use more accurate methods like spectrophotometer or colorimetry to read the results of AFST.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Shenoy M, Shenoy S. Superficial fungal infections. In: Sacchidanand S, editor. IADVL Textbook of Dermatology. 4th ed. Mumbai (India): Bhalani; 2015. p. 459-567.  Back to cited text no. 1
    
2.
Nigam PK. Antifungal drugs and resistance: Current concepts. Our Dermatol Online 2015;6:212-21.  Back to cited text no. 2
    
3.
Gandhi S, Patil S, Patil S, Badad A. Clinicoepidemiological study of dermatophyte infections in pediatric age group at a tertiary hospital in Karnataka. Indian J Pediatr Dermatol 2019;20:52-6.  Back to cited text no. 3
    
4.
Doss RW, El-Rifaie AA, Radi N, El-Sherif AY. Antimicrobial susceptibility of tinea capitis in children from Egypt. Indian J Dermatol 2018;63:155-9.  Back to cited text no. 4
[PUBMED]  [Full text]  
5.
CLSI. Reference Method for Broth Dilution Antifungal Susceptibility Testing of Filamentous Fungi; Approved Standard—2nd Edition. CLSI document M38-A2. Wayne, PA: Clinical and Laboratory Standards Institute; 2008.  Back to cited text no. 5
    
6.
Ajello L, Georg LK. In vitro hair cultures for differentiating between atypical isolates of Trichophyton mentagrophytes and Trichophyton rubrum. Mycopathol Mycol Appl 1957;8:3-17.  Back to cited text no. 6
    
7.
Deng S, Ansari S, Ilkit M, Rafati H, Hedayati MT, Taghizadeh-Armaki M, et al. In vitro antifungal susceptibility profiles of 12 antifungal drugs against 55 Trichophyton schoenleinii isolates from Tinea Capitis Favosa Patients in Iran, Turkey, and China. Antimicrob Agents Chemother 2017;61:e01753-16.  Back to cited text no. 7
    
8.
Santos DA, Hamdan JS. Evaluation of broth microdilution antifungal susceptibility testing conditions for Trichophyton rubrum. J Clin Microbiol 2005;43:1917-20.  Back to cited text no. 8
    
9.
Baghi N, Shokohi T, Badali H, Makimura K, Rezaei-Matehkolaei A, Abdollahi M, et al. In vitro activity of new azoles luliconazole and lanoconazole compared with ten other antifungal drugs against clinical dermatophyte isolates. Med Mycol 2016;54:757-63.  Back to cited text no. 9
    
10.
Mishra N, Rastogi MK, Gahalaut P, Yadav S, Srivastava N, Aggarwal A. Clinicomycological study of dermatophytoses in children: Presenting at a tertiary care center. Indian J Pediatr Dermatol 2018;19:326-30.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 
    Tables

  [Table 1], [Table 2]



 

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