How to identify a subcutaneous mite? - briefly
Detection relies on visual examination of skin lesions, followed by skin scraping and microscopic analysis to observe characteristic mite morphology such as elongated bodies and specialized mouthparts. Confirmation may require dermatoscopic imaging or molecular assays for species‑level identification.
How to identify a subcutaneous mite? - in detail
Subcutaneous mites reside beneath the skin surface, often producing localized inflammation, nodules, or ulcerations. Accurate detection relies on a combination of clinical observation, specimen acquisition, and laboratory analysis.
Clinical clues include:
- Erythematous or violaceous papules that may coalesce into larger plaques.
- Presence of palpable, firm nodules, sometimes fluctuating.
- Pruritus or pain associated with the lesions.
- History of exposure to animals or endemic regions where such arthropods are prevalent.
Specimen collection procedures:
- Clean the affected area with antiseptic solution.
- Apply a sterile dermal punch (2–4 mm) to obtain a full‑thickness skin sample, ensuring inclusion of the epidermis and underlying dermis.
- Place the biopsy in saline or ethanol, depending on the intended analysis.
- For superficial lesions, gently scrape the surface with a sterile scalpel blade to gather any migrating mites.
Microscopic examination:
- Prepare wet mounts in saline; examine under low (10×) and high (40×) magnification for motile organisms.
- Stain fixed sections with hematoxylin‑eosin or Giemsa to highlight mite morphology: round body, four pairs of legs, and characteristic gnathosoma.
- Identify species based on size, leg segmentation, and setal patterns.
Molecular confirmation:
- Extract DNA from the tissue using a commercial kit, following the manufacturer’s protocol.
- Perform polymerase chain reaction with primers targeting the mitochondrial 12S rRNA gene, a conserved region in subcutaneous mites.
- Verify amplicon size by electrophoresis; sequence the product for species‑level identification.
Additional diagnostic tools:
- Dermoscopy may reveal characteristic “white‑gray” structures corresponding to mite bodies.
- Ultrasonography can detect hypoechoic nodules suggestive of mite burrows.
Integration of clinical signs, histopathology, and molecular data provides definitive identification, guiding appropriate therapeutic interventions.