What does a subcutaneous tick look like to the eye? - briefly
A subcutaneous tick presents as a tiny, slightly raised, flesh‑colored nodule with a central punctum marking the embedded mouthparts. The surrounding skin may show a faint erythematous halo, while the tick itself remains largely invisible as a distinct organism.
What does a subcutaneous tick look like to the eye? - in detail
A tick that has migrated beneath the epidermis presents as a discrete, raised nodule. The lesion is typically oval or circular, measuring 2–10 mm in diameter depending on the stage of engorgement. Color ranges from light brown in early attachment to dark brown or black when the abdomen fills with blood. The surface may appear smooth or slightly wrinkled, reflecting the cuticle of the arthropod.
A central punctum often marks the point where the mouthparts penetrate the skin. This tiny opening may be visible as a pinpoint depression or a faint, dark line. Surrounding the nodule, the surrounding dermis can show mild erythema or a halo of inflammation, especially if the host’s immune response is active. In some cases, a thin, translucent membrane covers the tick, giving the impression of a clear blister over a dark core.
When palpated, the structure feels firm but not hard, distinguishing it from calcified cysts or foreign bodies. An engorged subcutaneous tick may feel slightly pliable due to the blood load, whereas a partially fed specimen remains relatively rigid.
Key visual cues include:
- Oval or round elevation, 2–10 mm size
- Brown to black coloration, darkening with engorgement
- Central punctum or minute line indicating mouthpart entry
- Mild surrounding erythema or inflammatory halo
- Firm, slightly pliable consistency on palpation
- Possible translucent covering resembling a thin blister
Dermatoscopic examination enhances visibility of the central punctum and the tick’s legs, which may appear as faint, radiating structures beneath the skin surface. Absence of these features suggests alternative diagnoses such as epidermoid cysts, granulomas, or retained foreign material.