Sensitivity and specificity of traditional testing methods to detect sensory impairment in the skin lesions of leprosy compared to Semmes–Weinstein monofilaments

Anitha Ramachandran,Biju George,Keerankulangara Devi,Kidangazhiyathmana Ajithkumar,Lulua Safar,Sarita Sasidharanpillai

doi:10.47276/lr.91.1.89

Abstract

Objective: To determine the sensitivity and specificity of traditional testing methods to detect sensory deficit in the skin lesions of leprosy in comparison to Semmes Weinstein (SW) nylon monofilaments. Design: After ethical clearance and written informed consent from study subjects, a consecutive series of 50 patients aged >12 years with leprosy skin lesions, who attended our institution, were evaluated in this cross sectional study. Results: 74 skin lesions of 50 patients were evaluated. Considering the monofilament test result as the gold standard, the sensitivity to detect sensory impairment was 95.9% for the ballpoint pen, 97.3% for a sterile needle and 100% for cotton wool, and cold and warm water. Limitation: Paucity of cases in the lepromatous spectrum of disease and the probable absence of early lesions of disease in the study group were the study limitations. Conclusions: The cotton wool and ballpoint pen methods are easy to perform in the field and have comparable sensitivity and specificity to the blue Semmes Weinstein nylon monofilament to detect sensory impairment in skin lesions, especially in tuberculoid cases.

Highlights

Despite the elimination of leprosy as a problem of public health importance, new cases continue to be reported.[1]
Peripheral centres generally use the tip of a ballpoint pen, while many tertiary referral centres make use of cotton wool, as well as the point of a sterile needle, and cold (25 °C) and warm water (40 °C–45 °C as per various studies) in test tubes, to detect sensory impairment.[3,4]
The study population comprised of 50 patients with skin lesions diagnostic of Hansen’s disease (Table 2)

Summary

Introduction

Despite the elimination of leprosy as a problem of public health importance, new cases continue to be reported.[1] Early diagnosis and treatment is the recommended strategy to break the chain of disease transmission.[1] Leprosy is diagnosed by the cardinal signs proposed by WHO.[2] Patients having one of the three signs (asymptomatic hypopigmented or erythematous skin lesion with sensory impairment; thickened peripheral nerve with sensory impairment over the area supplied by the nerve; acid fast bacilli positivity in skin smear studies) are diagnosed to have leprosy. Detection of defective sensory perception is significant in diagnosing leprosy. Peripheral centres generally use the tip of a ballpoint pen (to test light touch), while many tertiary referral centres make use of cotton wool (for light touch), as well as the point of a sterile needle (for pain), and cold (25 °C) and warm water (40 °C–45 °C as per various studies) in test tubes (for temperature), to detect sensory impairment.[3,4] But these traditional methods are not standardised

Methods

Results

Conclusion