What Do Sand Fleas Look Like?
Sand fleas (Tunga penetrans), also known as chigoe fleas or jiggers, are tiny parasitic fleas that are difficult to see with the naked eye, especially before they burrow into the skin. Here's what sand fleas look like:
Free-Living (Unattached) Adult Flea
Size: Extremely small — about 1 millimeter long (roughly the size of a grain of sand).
Color: Pale brown to yellowish in color, which helps them blend in with sandy soil.
Shape: Flat, wingless body with a rounded abdomen and long hind legs adapted for jumping.
Features: The female is slightly larger than the male. They move quickly and are often found in sandy, dry areas near beaches, farms, or animal pens.
Embedded (Parasitic) Female
Once the female flea burrows into a host’s skin—usually the feet, toes, or under toenails—she undergoes a dramatic transformation:
Appearance under the skin: A small, white to yellowish bump forms, often with a black central dot (the flea’s exposed rear end used for breathing and egg-laying). The swelling can reach 5–10 millimeters in diameter as the flea’s abdomen expands with eggs.
Texture: The lesion becomes firm, round, and slightly raised, sometimes resembling a wart, blister, or pimple.
Behavior: Over 1–2 weeks, the flea lays hundreds of eggs, which are expelled through the central pore before she dies and the skin lesion becomes crusted.
Key Identification Points
Tiny, sand-colored flea that burrows into skin, unlike most fleas which only bite and jump away.
Common entry points: soles of feet, between toes, or around toenails.
Hosts: Humans, dogs, pigs, and other mammals.
How Big Are Sand Fleas?
The size of sand fleas (Tunga penetrans) depends on their stage of life and whether they’re free-living or embedded in a host:
Free-Living Adult Sand Flea
Length: Only about 1 millimeter (0.04 inches) long — roughly the size of a grain of sand or a pinhead.
Males: Slightly smaller than females.
Comparison: About 5–10 times smaller than a common cat flea (Ctenocephalides felis), which is typically 2–3 mm long.
Because they are so tiny and pale, they’re very hard to see when moving around in sand or soil.
Embedded (Parasitic) Female
Once a female sand flea burrows into a host’s skin, she swells dramatically as her abdomen fills with eggs.
Initial size (before burrowing): ~1 mm
After engorgement: Up to 5–10 millimeters (0.2–0.4 inches) in diameter
The embedded flea causes a raised, white or yellowish bump on the skin with a dark central dot (her exposed rear end).
What Color Are Sand Fleas?
Sand fleas (Tunga penetrans) are very small, and their coloration changes slightly depending on whether they are free-living or embedded in a host:
Free-Living Adult Sand Fleas
Color: Typically light brown, tan, or yellowish in hue. Their coloration closely matches sandy soil, which provides excellent camouflage.
Texture and appearance: Slightly shiny or translucent under magnification. The body may appear pale amber when viewed in good light.
Because of their small size (around 1 mm) and muted color, they’re extremely difficult to spot against the sand.
Embedded (Parasitic) Female
Once the female burrows into a host’s skin and begins swelling with eggs, her appearance changes dramatically:
Color under the skin: The body becomes whitish, creamy, or yellowish, as the abdomen expands beneath the skin. The dark central spot (usually black or dark brown) visible at the center of the lesion is the flea’s rear end, which remains exposed for breathing and egg-laying.
Over time, as the embedded flea dies and the skin reacts, the area may turn reddish, purplish, or brown due to inflammation and scabbing.