How can one distinguish dandruff from lice and lice eggs on a person?

How can one distinguish dandruff from lice and lice eggs on a person? - briefly

Dandruff consists of loose, white, powdery flakes that fall off easily and show no live insects, while lice are small, brownish insects that move on the scalp and can be seen with a fine-tooth comb. Their eggs appear as oval, yellow‑brown nits firmly glued to the hair shaft close to the scalp, not easily removable.

How can one distinguish dandruff from lice and lice eggs on a person? - in detail

Scalp flakes, head lice, and their eggs each have distinct visual and tactile features that allow reliable identification.

• Appearance

  • Dandruff consists of white‑to‑light‑gray powdery particles that easily detach from the scalp and float in the air when the hair is brushed.
  • Adult lice are brownish or gray insects, 2–4 mm long, with a flattened body and six legs. Their bodies are visible on the hair shaft, especially near the scalp.
  • Lice eggs (nits) are oval, about 0.8 mm in length, and appear as creamy‑white or yellowish shells firmly glued to the hair shaft at a 45‑degree angle. The shell’s surface is smooth and glossy.

• Attachment

  • Flakes are not attached; they fall off with minimal disturbance.
  • Lice cling to hair using clawed legs; they move quickly when the hair is touched.
  • Nits are cemented with a strong, transparent secretion that cannot be removed by simple brushing. They remain in place for up to a week before hatching.

• Location on the scalp

  • Dandruff is distributed evenly across the scalp and may appear on shoulders.
  • Lice prefer warm, protected areas such as behind the ears, the nape of the neck, and the crown.
  • Nits are most often found close to the scalp in the same regions where adult lice reside, because they require temperature for development.

• Sensations

  • Dandruff causes no itching beyond possible irritation from dryness.
  • Lice infestations produce intermittent itching due to bite reactions; the scalp feels restless and may develop small red papules.
  • Nits themselves are not itchy, but the presence of adult lice that feed on blood triggers the itch.

• Diagnostic methods

  1. Visual inspection – Use a bright light and a fine-tooth comb to separate hair strands. Observe for live insects and attached eggs.
  2. Magnification – A handheld magnifier (10×) clarifies the shape of nits and the legs of lice.
  3. Wet mount – Place a few hairs on a slide with a drop of saline; examine under a microscope to confirm species.
  4. Physical removal test – Attempt to slide a nit along the hair shaft; true nits will resist movement, while dandruff particles slide off easily.

• Treatment implications

  • Dandruff responds to antifungal shampoos containing zinc pyrithione, selenium sulfide, or ketoconazole.
  • Lice require topical pediculicides (e.g., permethrin 1 % or dimethicone) applied to the scalp and repeated after 7–10 days to kill newly hatched insects.
  • Nits are eliminated by meticulous combing with a fine-tooth nit comb, followed by washing of all bedding and personal items at high temperature.

By evaluating particle size, attachment strength, location, and the presence of movement, one can accurately differentiate between scalp flakes, head lice, and their eggs.