Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
  • Users Online: 60
  • Home
  • Print this page
  • Email this page


 
 Table of Contents  
ORIGINAL ARTICLES
Year : 2021  |  Volume : 8  |  Issue : 2  |  Page : 57-60

Evaluation of fungal elements in dystrophic nails using Chicago sky blue stain


Department of Dermatology, Venereology and Leprology, Victoria Hospital, Bengaluru, Karnataka, India

Date of Submission01-Feb-2021
Date of Decision27-Jun-2021
Date of Acceptance05-Jul-2021
Date of Web Publication06-Oct-2022

Correspondence Address:
Sowmya S Aithal
4753/A, Sindhoora, Opposite Jyothi IVF Centre, Dattagalli 3rd Stage, Mysore 570022, Karnataka
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijdpdd.ijdpdd_14_21

Rights and Permissions
  Abstract 

Background: Dystrophic nails represent an alteration in nail morphology that can occur due to various disorders. Although KOH is used commonly in the diagnosis, the sensitivity and specificity of KOH are less. Chicago sky blue (CSB) stain when used with KOH provides color contrast, to aid the detection of fungal elements, and is a simple and inexpensive method. Materials and Methods: Nail scrapings from the surface and subungual areas and nail clippings were examined with 40% KOH, CSB stain, and also subjected to fungal culture. Results: The detection rate of fungal elements in dystrophic nails in our hospital-based study was 46.5%. The sensitivity of KOH was 36.36% and CSB staining was 66.6% using fungal culture as a gold standard. Conclusion: CSB stain serves as a useful, simple, and rapid method for detecting the presence of fungal elements.

Keywords: Chicago sky blue stain, dystrophic nails, onychomycosis


How to cite this article:
Revathi T N, Aithal SS. Evaluation of fungal elements in dystrophic nails using Chicago sky blue stain. Indian J Dermatopathol Diagn Dermatol 2021;8:57-60

How to cite this URL:
Revathi T N, Aithal SS. Evaluation of fungal elements in dystrophic nails using Chicago sky blue stain. Indian J Dermatopathol Diagn Dermatol [serial online] 2021 [cited 2023 Feb 8];8:57-60. Available from: https://www.ijdpdd.com/text.asp?2021/8/2/57/357932




  Introduction Top


Onychodystrophy represents various pathologic processes of the nails including infectious and non-infectious diseases such as onychomycosis, psoriasis, and irritant and allergic dermatitis. The most frequent nail disorders are onychomycosis (30–40%) and nail psoriasis.[1]

Potassium hydroxide (KOH) preparation and fungal culture, which are typically utilized in the diagnosis of fungal infections, often yield false-negative results.[2] Chicago sky blue (CSB) is a new stain, which contains 1% CSB 6B and is used with KOH. It provides color contrast that helps in the easier detection of fungal elements even when they are scanty.

Aims and objectives

The aim of this article is to detect the presence of fungal elements in scrapings from the surface and subungual areas of dystrophic nails with CSB stain and to compare the efficacy of CSB stain-KOH with KOH and fungal culture.


  Materials and Methods Top


Institutional Ethical Committee clearance was obtained for this cross-sectional study conducted on 71 patients presenting with dystrophic nails. Patients of age 18–60 years and of either sex presenting with dystrophic nails, defined as an alteration in nail morphology manifesting as misshapen and damaged nails, were included. Patients who were already on antifungal treatment for onychomycosis were excluded.

After history taking and clinical examination, nail scrapings from the surface and subungual areas and nail clippings were taken and divided into three parts. One part was examined after adding a drop of 40% KOH after 30 min. The second part was treated with KOH–1% CSB combination and examined under the microscope at 10× and 40× magnifications after 10 min. CSB stain was prepared by dissolving 1 g of CSB dye in 100 mL of distilled water forming a 1% solution. The third part of the sample was subjected to fungal culture.


  Results Top


In our study, 54% were males, and the remaining 46% were females. The highest prevalence (47.8%) was seen in participants of the age group 40–60 years and the lowest prevalence (4.22%) in participants younger than 20 years. Of 71 cases, 22.5% of the participants were housewives, 12.7% were farmers, 12.7% were students, 9.85% were laborers, and the remaining 42.25% performed other occupations.

The most common clinical type in our study was distal and lateral subungual onychomycosis (DLSO) in 63.6% of the cases, followed by proximal subungual onychomycosis [Figure 1]. Dermatophytes were the most commonly found pathogens (57.57%), followed by non-dermatophyte molds isolated in about 24.24% of the participants. Among the dermatophytes, Trichophyton rubrum was the most frequently isolated in about 33.33% of the participants [Table 1].
Figure 1: Frequency distribution of patients according to clinical type of onychomycosis

Click here to view
Table 1: Frequency distribution of fungal isolates observed by clinical pattern

Click here to view


Among the 71 patients who presented with dystrophic nails, fungal elements could be detected in 33 (46.48%) patients by fungal culture. KOH preparation alone could detect fungal elements only in 12 (16.9%) cases, whereas CSB stain could detect in 22 (30.9%) cases [Figure 2] and [Figure 3]. False-negative results were found in 22 cases with KOH and in 11 cases with CSB staining, i.e., 10 nails that were shown negative by KOH could be detected by CSB stain with the aid of color contrast [Figure 4]. Comparison of results of direct microscopy with KOH, CSB stain, and fungal culture in the diagnosis of onychomycosis is depicted in [Table 2] and [Table 3].
Figure 2: CSB stain of nail sample showing fungal elements with color contrast (10×)

Click here to view
Figure 3: Bluish septate hyphae seen with faint pink background in CSB stain under 40×

Click here to view
Figure 4: Fungal filaments identified in the slide with 1% CSB that was negative for potassium hydroxide preparation

Click here to view
Table 2: Comparison of results of direct microscopy with KOH and fungal culture in the diagnosis of onychomycosis

Click here to view
Table 3: Comparison of results of direct microscopy with CSB stain and fungal culture in the diagnosis of onychomycosis

Click here to view


With fungal culture as the gold standard, the sensitivity of KOH was 36.36% and CSB stain was 66.6% and their specificity came out to be 100% (P < 0.01), suggesting CSB sensitivity to be superior to KOH.


  Discussion Top


The detection rate of fungal elements in dystrophic nails in our hospital-based study was 46.5%. Few studies have shown isolation rates of 39.5% in Central Delhi, India[3] and 37.6% in Himachal Pradesh, India.[4] Many patients with dystrophic nails may not seek medical attention, which explains the difference in the prevalence observed.

Higher prevalence in elderly patients can be due to the presence of repeated trauma, poor immunity, other comorbidities, and increased duration of exposure to causative fungi.[5]

Males are more predisposed than females because of nail damage from increased outdoor exposure, more physical activity, and frequent use of occlusive footwear.[6]

Housewives are more involved in household work like washing clothes, vegetables, and cleaning house, which makes them prone to trauma and exposure to moisture.[7] Farmers and laborers have frequent physical trauma due to their nature of work making them prone to dystrophy.

In our study, patients presented to us with different cutaneous features. The most common association was psoriasis in 14% of cases. Other associations included eczema (8.45%), Tinea corporis (7.04%), lichen planus (4.22%), pemphigus vulgaris (4.22%), Tinea cruris (2.81%), bullous pemphigoid (2.81%), and atopic dermatitis (1.4%). Dystrophic nails in psoriatic patients lose their natural preventing barrier and thus are more predisposed to fungal infection. Nail psoriasis acts as a risk factor specifically for dermatophytic nail infections.[8]

Of the 71 patients with dystrophic nails, 43.48% were shown to have fungal elements by culture, 30.9% by CSB stain, and only 16.9% by KOH in our study. The sensitivity of CSB stain was higher than that of KOH.

KOH examination alone will lead to significant under-diagnosis of cases, whereas fungal culture increases the gap between diagnosis and cure because it requires weeks for growth and the yield is also poor.[9]

Staining with CSB requires 10 min in addition to KOH preparation that requires 40 min. Hence, it is a rapid and inexpensive method using a simple microscope. It provides good color contrast in comparison to KOH, helping in the rapid detection of fungal elements. It also highlights the morphology of fungi helping in the detection of yeast and hyphae.[10]

Studies have shown that the CSB is more sensitive and more specific than the KOH preparation.[11] The cost for a 25 g bottle of CSB, which stains about 1500 specimens, is only 3500₹ and thus economical.

Many studies have shown several staining procedures like Calcofluor-White Stain and KOH-Acridine Orange Stain, helpful for the rapid detection of fungal elements but they are expensive and require a fluorescent microscope.[12],[13]

Histopathological examination of nail clippings with PAS stain renders diagnosis in a short time and more sensitive than KOH and culture.[14] But it is an invasive method, does not identify the particular pathogen and serum inclusions may be mistaken for fungi which are also PAS-positive.[6]

Fungal culture is considered as a gold standard for mycological examination but it requires weeks for results and the yields are poor.[15]

The presence of fungal elements in dystrophic nails can act as a reservoir of fungus which may spread to other areas. It is important to establish a diagnosis before starting patients on a long course of antifungal treatment. The limitations of this study include a small study group.


  Conclusion Top


In conclusion, the present study shows 46.5% of dystrophic nails to be of fungal etiology and CSB stain could detect 30.9% of cases. Dystrophic nails caused by different conditions pose a diagnostic challenge and mycological examination is required to start patients on a long course of antifungal treatment in addition to clinical examination. Hence, CSB stain serves as a useful, simple, and rapid method for detecting the presence of fungal elements, which is less skill dependent than the routine KOH preparation and requires only an ordinary light microscope, compared with other stains which require a fluorescent microscope for examination.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Oppel T, Korting HC Onychodystrophy and its management. Ger Med Sci 2003;1:Doc02.  Back to cited text no. 1
    
2.
Weinberg JM, Koestenblatt EK, Tutrone WD, Tishler HR, Najarian L Comparison of diagnostic methods in the evaluation of onychomycosis. J Am Acad Dermatol 2003;49:193-7.  Back to cited text no. 2
    
3.
Sanjiv A, Shalini M, Charoo H Etiological agents of onychomycosis from a tertiary care hospital in Central Delhi, India. Indian J Fundam Appl Life Sci 2011;1:11-4.  Back to cited text no. 3
    
4.
Gupta M, Sharma NL, Kanga AK, Mahajan VK, Tegta GR Onychomycosis: Clinico-mycologic study of 130 patients from Himachal Pradesh, India. Indian J Dermatol Venereol Leprol 2007;73:389-92.  Back to cited text no. 4
    
5.
Singal A, Khanna D Onychomycosis: Diagnosis and management. Indian J Dermatol Venereol Leprol 2011;77:659-72.  Back to cited text no. 5
    
6.
Kaur R, Kashyap B, Bhalla P Onychomycosis—Epidemiology, diagnosis and management. Indian J Med Microbiol 2008;26:108-16.  Back to cited text no. 6
    
7.
Jesudanam TM, Rao GR, Lakshmi DJ, Kumari GR Onychomycosis: A significant medical problem. Indian J Dermatol Venereol Leprol 2002;68:326-9.  Back to cited text no. 7
    
8.
Kaçar N, Ergin S, Ergin C, Erdogan BS, Kaleli I The prevalence, aetiological agents and therapy of onychomycosis in patients with psoriasis: A prospective controlled trial. Clin Exp Dermatol 2007;32:1-5.  Back to cited text no. 8
    
9.
Adekhandi S, Pal S, Sharma N, Juyal D, Sharma M, Dimri D Incidence and epidemiology of onychomycosis in patients visiting a tertiary care hospital in India. Cutis 2015;95:E20-5.  Back to cited text no. 9
    
10.
Nargis T, Shenoy MM, Bejai V, Gopal V A simple but yet novel stain in the diagnosis of onychomycosis. Indian J Dermatopathol Diagn Dermatol 2018;5:39.  Back to cited text no. 10
    
11.
Lim CS, Lim SL Practical tip: Chicago sky blue (CSB) stain can be added to the routine potassium hydroxide (KOH) wet-mount to provide a color contrast and facilitate the diagnosis of dermatomycoses. Dermatol Online J 2011;17:11.  Back to cited text no. 11
    
12.
Haldane DJ, Robart E A comparison of Calcofluor white, potassium hydroxide, and culture for the laboratory diagnosis of superficial fungal infection. Diagn Microbiol Infect Dis 1990;13:337-9.  Back to cited text no. 12
    
13.
Panasiti V, Borroni RG, Devirgiliis V, Rossi M, Fabbrizio L, Masciangelo R, et al. Comparison of diagnostic methods in the diagnosis of dermatomycoses and onychomycoses. Mycoses 2006;49:26-9.  Back to cited text no. 13
    
14.
Shenoy MM, Teerthanath S, Karnaker VK, Girisha BS, Krishna Prasad MS, Pinto J Comparison of potassium hydroxide mount and mycological culture with histopathologic examination using periodic acid-Schiff staining of the nail clippings in the diagnosis of onychomycosis. Indian J Dermatol Venereol Leprol 2008;74:226-9.  Back to cited text no. 14
    
15.
Burke WA, Jones BE A simple stain for rapid office diagnosis of fungus infections of the skin. Arch Dermatol 1984;120:1519-20.  Back to cited text no. 15
    


    Figures

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

  [Table 1], [Table 2], [Table 3]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Materials and Me...
Results
Discussion
Conclusion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed697    
    Printed34    
    Emailed0    
    PDF Downloaded52    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]