How do lice nits appear? - briefly
Nits are the eggs laid by female head lice, which are glued to hair strands close to the scalp with a firm, protein‑based secretion. They appear as small, oval, white‑to‑yellow specks that are firmly attached and do not flake off like dandruff.
How do lice nits appear? - in detail
Lice eggs, commonly called nits, are laid by adult female head‑lice (Pediculus humanus capitis) during the reproductive phase of their life cycle. Each female can deposit up to eight eggs per day, attaching them firmly to the hair shaft with a cement‑like secretion that hardens within minutes. This adhesive bonds the nit to the cuticle of the hair, typically within 1 mm of the scalp where temperature and humidity support embryonic development.
The egg itself measures about 0.8 mm in length and 0.3 mm in width. Initially, the shell appears translucent or pale yellow, making it difficult to distinguish from hair or skin debris. As the embryo matures, the shell darkens to a tan or brown hue, and the shape becomes more defined, often resembling a tiny teardrop or oval. The visible change results from the accumulation of pigment in the developing nymph and the thickening of the chitinous wall.
Key stages of nit appearance:
- Deposition: Female louse attaches the egg at an angle of 30–45° to the hair shaft, using a proteinaceous glue that resists removal by brushing or washing.
- Incubation (5–7 days): Egg remains opaque; color may shift slightly as the embryo grows.
- Maturation (last 1–2 days): Shell darkens, becomes more opaque; nymph pushes against the inner wall, creating a faint outline.
- Hatching: Nymph chews a small exit hole, leaving an empty, hollow shell that retains the original shape and color but is now brittle.
Visibility is enhanced when:
- The hair is light‑colored, providing contrast with the darker nit.
- The scalp is clean, reducing background debris.
- The nit is located close to the scalp, where warmth accelerates development and pigmentation intensifies.
Detection relies on visual inspection with magnification (10× handheld loupes or a microscope). Inspectors look for the characteristic angle of attachment, the teardrop silhouette, and the presence of a solid, non‑transparent shell. Empty shells, often called “nits,” remain attached after hatching and can be mistaken for live eggs; they are typically more translucent and may crumble under gentle pressure.
Understanding these morphological and developmental cues enables accurate identification of lice eggs and informs effective treatment and removal strategies.