Predictive values of 10% potassium hydroxide examination for superficial fungal infection of the skin

Introduction Ten percent potassium hydroxide examination is one of the most frequently performed tests in dermatology. It is usually supplemented by fungal culture for detection of superficial fungal infection of the skin and its appendages. We aim to determine the predictive values of 10% potassium hydroxide examination in Sarawak General Hospital. Materials and Methods A retrospective review of 292 skin scraping results for 10% potassium hydroxide examination and culture was done between October 2003 and December 2004. Data for all the scrapings were analysed for predictive values, specificity, sensitivity and likelihood ratio with fungal culture as the gold standard investigation. Separate data analysis was done for those with onychomycosis. Results Positive cultures were noted in 80.8% of skin scrapping cases and 85.4% of onychomycosis cases. For the skin scrapping cases, the positive predictive value of 10% potassium hydroxide examination was 67.4%, negative predictive value of 16.9%, sensitivity of 12.3% and specificity of 75%. For those with onychomycosis, the positive predictive value was 75%, negative predictive value 13.6%, specificity 85.7% and sensitivity was 7.3%. The positive likelihood ratio for all cases and onychomycosis cases was 0.5 whereas the negative likelihood ratio was 0.9. Conclusion Ten percent potassium hydroxide examination has a very low negative predictive value and sensitivity, making it a poor investigative tool in Sarawak General Hospital. Thus, culture of the skin scraping for suspected superficial fungal infection of the skin and its appendages is of utmost importance. Steps to improve the quality of 10% potassium hydroxide examination are important as it is an easy and inexpensive test.

A 4-year retrospective study of Stevens-Johnson syndrome and toxic epidermal necrolysis

Background Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare bullous mucocutaneous disease usually caused by drugs. We aim to determine the demographics, causes and outcomes of patients admitted with SJS, TEN and SJS-TEN overlap in Sarawak General Hospital. Materials and Methods A retrospective review of cases admitted to Sarawak General Hospital with SJS, TEN and SJS-TEN overlap from January 2004 to December 2007 was undertaken. Data regarding the demographic, causes and outcomes were collected from the case folders and subjected to descriptive statistical analysis using Microsoft Excel. Results Twenty four cases were admitted with 54.2% having SJS, 25% having SJS-TEN Overlap and 20.8% having TEN. With the mean ages of more than 40 years, patients with SJS and SJS-TEN overlap were older than patients with TEN, with a mean age of only 25.4 years. Seventy nine percent of cases were drugs induced. Anticonvulsants were the main culprit constituting 29.2% followed by allopurinol with 20.8%. Cases with SJS had the longest incubation period with mean of 21.6 days whereas cases with TEN had the longest mean hospital stay with 12.4 days. A 12.5% mortality rate was recorded with 2 deaths in the SJS-TEN overlap group and one death in the TEN group. All cases who were given intravenous immunoglobulin (IVIg) survived. Conclusion SSJS, SJS-TEN Overlap and TEN were mainly drug induced and have high mortality. IVIg treatment seems promising. Early recognition and optimal care in institution with dermatology service is essential in reducing morbidities and mortalities.