Clinico-cytological study of dermatophytic infections and interobserver agreement of potassium hydroxide mount diagnosis: A prospective cross-sectional study at a tertiary care centre.

Dr. Tulasi Jarang; Dr. Pavani Kusuma; Dr. Fawwad M. Shaikh

doi:10.51168/ccvz3564

Authors

Dr. Tulasi Jarang Professor and Head, Department of Dermatology, Venereology and Leprosy, Government Medical College, Khammam, Telangana, India.
Dr. Pavani Kusuma Assistant Professor, Department of Dermatology, Venereology and Leprosy, Government Medical College, Khammam, Telangana, India
Dr. Fawwad M. Shaikh Professor and Head, Department of Community Medicine, Government Medical College, Bhadradri Kothagudem, Telangana, India.

DOI:

https://doi.org/10.51168/ccvz3564

Keywords:

Dermatophytosis, Potassium hydroxide mount, Tinea corporis, cytology, Interobserver agreement, Cross-sectional study

Abstract

Background

Objectives: To determine potassium hydroxide mount positivity among clinically diagnosed dermatophytic infections, compare positivity between treatment-naive and previously treated patients, describe positivity across clinical subgroups, and quantify interobserver agreement between a faculty observer and a senior resident.

Methods

This prospective, hospital-based cross-sectional study was conducted at Government Medical College/Government General Hospital, Suryapet, from January 2021 to December 2022. Among 7,435 patients clinically diagnosed with dermatophytosis during the study period, potassium hydroxide mount examination was performed in 1,182 (15.9%), who constituted the analytical cohort. Skin scrapings, nail clippings, or hair samples were processed using tissue-appropriate potassium hydroxide concentrations. The same preparations were interpreted by an Associate Professor and a senior resident, and agreement was assessed using Cohen's kappa.

Results

Of 7,435 clinically diagnosed dermatophytosis cases, 1,182 underwent potassium hydroxide mount examination (15.9%). Among the tested participants, 711 were KOH-positive (60.2%; 95% CI, 57.3%-62.9%). Positivity did not differ by sex (χ²(1) = 0.053, p = .817), but varied by age group (χ²(6) = 26.088, p < .001). Treatment-naive patients had higher positivity than previously treated patients (74.5% vs 45.7%; χ²(1) = 102.236, p < .001; odds ratio = 3.47, 95% CI, 2.71-4.43). Tinea corporis contributed 193 of 711 positive results (27.1%), followed by infection at two or more sites (179/711, 25.2%); positivity differed across clinical types (χ²(8) = 35.290, p < .001). Overall observer agreement was 93.3%, with κ = 0.86 (95% CI, 0.83-0.89; p < .001).

Conclusion

Potassium hydroxide mount provided a clinically useful diagnostic yield and showed excellent reproducibility between observers. Standardized specimen collection, microscopy, and supervised observer training can strengthen its reliability in high-volume dermatology services.

Recommendations

Regular hands-on training, standardized sampling, and quality review of negative or discordant slides are recommended in teaching hospitals.

Author Biographies

Dr. Tulasi Jarang, Professor and Head, Department of Dermatology, Venereology and Leprosy, Government Medical College, Khammam, Telangana, India.

is working as Professor in the Department of Dermatology, Venereology and Leprosy at Government Medical College, Khammam, Telangana, India. She completed her MBBS from Kakatiya Medical College, Warangal, and MD in Dermatology, Venereology and Leprosy from Gandhi Medical College, Secunderabad. She previously served as Assistant Professor at Gandhi Medical College, Secunderabad, for six years and as Associate Professor at Government Medical College, Khammam, for two years before assuming her present position as Professor at the same institution. Her ORCID ID: https://orcid.org/0009-0004-6026-4750
Dr. Pavani Kusuma, Assistant Professor, Department of Dermatology, Venereology and Leprosy, Government Medical College, Khammam, Telangana, India

is working as Assistant Professor in the Department of Dermatology, Venereology and Leprosy at Government Medical College, Khammam, Telangana, India. She completed her MBBS from Siddhartha Medical College, Vijayawada, and MD in Dermatology, Venereology and Leprosy from Mamata Medical College, Khammam, Telangana. She has two years of teaching experience and is actively involved in undergraduate teaching, clinical dermatology services, and academic activities. Her ORCID ID: https://orcid.org/0009-0009-8685-2004
Dr. Fawwad M. Shaikh, Professor and Head, Department of Community Medicine, Government Medical College, Bhadradri Kothagudem, Telangana, India.

is working as a Professor in the Department of Community Medicine with 10 years of teaching experience. He completed his MD in Community Medicine from Belagavi Institute of Medical Sciences, Belagavi, and DNB from Wardha. His academic interests include geriatrics, public health, epidemiology, and sexually transmitted diseases. He has published several research papers in the field of geriatrics and continues to focus on community-based health research, including studies related to dermatological and sexually transmitted infections. His ORCID ID: https://orcid.org/0000-0002-9641-9097

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