Dr. Jared Gardner presents a rare dermatopathology case of Tungaiasis, a parasitic infestation caused by the Tunga penetrans sand flea (also known as jigger or Chico flea). The video details the flea's burrowing behavior beneath the stratum corneum, its distinct microscopic features, including a chitinous exoskeleton, and its geographical prevalence primarily in Central and South America, Africa, and India. The discussion highlights the flea's life cycle within the skin, contrasts its size and burrowing pattern with the much smaller scabies mite, and illustrates severe infestations often linked to poverty and walking barefoot. The case emphasizes the diagnostic importance of recognizing arthropod characteristics in skin biopsies.
Dermatopathology Fun: A Deep Dive into Tungaiasis
0:00 Introduction to Derm Path Fun: Dr. Jared Gardner begins a session on dermatopathology cases, starting with a unique example.
0:11 Case 1: Arthropod Infestation: The first slide presents an "arthropod organism" in the skin, prompting initial considerations of scabies, myiasis (botfly), and Tungaiasis.
1:08 Tungaiasis Identified: The case is definitively identified as Tungaiasis, caused by the Tunga penetrans sand flea, also known as the Chico or jigger flea. This condition is notably rare in the United States but prevalent in Central/South America, Africa, and India.
1:43 Burrowing Behavior: The sand flea burrows underneath the stratum corneum, creating a large, expanding cavity. It leaves a small hole through which it defecates and lays eggs before eventually dying and detaching.
2:00 Comparison to Scabies: While similar in burrowing pattern, the Tunga penetrans flea is significantly larger than a scabies mite.
3:13 Microscopic Features: The arthropod is characterized by a firm, yellowish or pink, refractile chitinous exoskeleton (a carbohydrate forming its outer shell). Internal organs and eggs are also visible. Recognizing chitin is a key takeaway for identifying arthropod infestations.
4:42 Host Response: The presence of the burrowed flea elicits a significant inflammatory response in the surrounding dermis, often with prominent eosinophils.
5:17 Clinical Presentation & Severity: External images illustrate the flea in its burrow (showing the egg extrusion hole), an extracted specimen, and severe infestations. These severe cases, dubbed "crusted Tungaiasis" (coined by Dr. Kayla Moore), often cluster around the lateral edges and soles of the feet, particularly in areas with high poverty rates and where individuals walk barefoot.
6:49 Case Conclusion: Dr. Gardner shares his enjoyment of this dramatic and rare slide, noting it's the first time he's shared this specific specimen.