What does a swollen tick look like? - briefly
A swollen tick presents as an enlarged, rounded organism with a noticeably distended abdomen that appears gray‑brown or reddish and looks more opaque than an unfed specimen. During engorgement it can grow to several millimeters, often reaching the size of a pea.
What does a swollen tick look like? - in detail
An engorged tick presents a markedly altered morphology compared to its unfed state. The body becomes distended, often resembling a small, translucent balloon. Size increases dramatically: many species expand from a few millimeters to 10–15 mm in length, with some reaching up to 20 mm when fully saturated with blood. The dorsal surface loses the distinct scutum pattern seen in unfed individuals; instead, a uniform, pale‑to‑yellowish hue dominates, occasionally showing a faint reddish tint where blood pools near the mouthparts.
Key visual indicators include:
- Rounded, swollen abdomen that dominates the overall silhouette, while the anterior capitulum (head) remains relatively unchanged.
- Smooth, glossy texture caused by the stretched cuticle, making the tick feel slick to the touch.
- Loss of distinct coloration; the tick often appears almost colorless, allowing underlying tissues to be visible through the cuticle.
- Visible legs that may appear splayed outward due to the increased body volume, though they remain proportionally smaller than the engorged body.
- Presence of a darkened mouthpart (hypostome) protruding from the anterior, sometimes surrounded by a faint halo of blood.
Differentiation among common species:
- Ixodes scapularis (black‑legged tick): engorged form exhibits an oval, almost spherical shape with a uniform gray‑white color.
- Dermacentor variabilis (American dog tick): after feeding, the body becomes more elongated, retaining a slight reddish‑brown tint on the dorsal surface.
- Amblyomma americanum (lone star tick): engorged individuals display a flattened, broad abdomen with a pale, almost translucent appearance.
When examining a suspected tick, assess size, coloration, and body shape in conjunction with the host’s attachment duration. Rapid identification of these characteristics aids in evaluating potential disease transmission risk.