Etiological Diagnosis of Scabies Based on Laboratory, Non-laboratory and Imaging Techniques

Human scabies, caused mostly by the mite Sarcoptes scabiei var hominis, is a globally prevalent, contagious skin disease that remains a major public health concern, particularly in resource-limited and overcrowded settings. Clinically, it presents with intense pruritus, especially at night, and a polymorphic rash that may include burrows, papules, nodules, or vesicles. However, these manifestations often overlap with other dermatological conditions such as eczema, contact dermatitis, or fungal infections, complicating clinical diagnosis. Compounding this challenge is the low mite burden in many cases, which frequently leads to false negatives in conventional diagnostic tests. This review synthesizes current diagnostic strategies based on laboratory, non-laboratory, and imaging techniques, evaluating their diagnostic utility and limitations. The gold standard—microscopic identification of mites, eggs, or fecal pellets from skin scrapings—although specific, suffers from reduced sensitivity due to the typically low mite load. Molecular techniques like polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) offer enhanced sensitivity and specificity by targeting mite DNA, yet their reliance on laboratory infrastructure limits their practicality in low-resource areas. Similarly, histopathological examination may reveal mite presence, but it is invasive and time-consumings. Non-laboratory technique such as the burrow ink test is easy to perform and cost-effective but lack diagnostic precision. Imaging modalities including dermoscopy, videodermoscopy (VD), reflectance confocal microscopy (RCM), and optical coherence tomography (OCT) represent significant advancements, allowing in vivo visualization of mites and burrows. These technologies enhance diagnostic accuracy and patient comfort, though their limited availability and high costs pose barriers to widespread implementation. Given the absence of a universally reliable single diagnostic tool, a more than one test approach that considers clinical presentation, resource availability, and patient factors is recommended. Standardizing such diagnostic pathways can reduce misdiagnosis, enhance treatment outcomes, and strengthen scabies control measures, especially in high-prevalence populations.

کلیدواژه ها:

Scabies ، Sarcoptes scabiei ، noninvasive techniques ، laboratory examination ، imaging