How can you tell whether it's dandruff or lice? - briefly
Examine the scalp: powdery white flakes that brush off easily point to dandruff, whereas live insects or brown‑black specks that cling to hair indicate lice. A fine‑tooth comb run through damp hair will capture nits if an infestation is present.
How can you tell whether it's dandruff or lice? - in detail
Distinguishing between a flaky scalp and an infestation of head parasites requires careful observation of visible signs, symptom patterns, and response to treatment.
Visible clues on the scalp and hair provide the first level of discrimination. Dandruff appears as light‑to‑medium gray or white flakes that detach easily from the scalp and fall onto shoulders. The flakes are typically dry, irregularly shaped, and do not cling to hair shafts. In contrast, head lice leave behind small, oval, opaque nits that are firmly attached to each hair strand about a quarter of an inch from the scalp. Nits are often mistaken for dandruff, but they remain fixed until manually removed, and they may be seen as a line of tiny specks along the hair line. Adult lice themselves are brownish, about the size of a sesame seed, and may be spotted moving quickly across the scalp.
Symptom patterns differ markedly. Dandruff usually causes mild itching, primarily after washing or in cold weather, without pain. The irritation does not intensify with close inspection of individual hairs. Lice infestation produces persistent, intense itching that worsens several hours after the scalp has been exposed to a warm environment, such as after a shower. Scratching may reveal small red bumps or secondary skin irritation caused by bites. Painful or tender areas are uncommon with dandruff.
Response to topical treatments offers a practical test. Antidandruff shampoos containing zinc pyrithione, selenium sulfide, or ketoconazole typically reduce flaking within a few washes. If flakes persist despite appropriate use, the likelihood of lice increases. Conversely, application of a pediculicide lotion (e.g., permethrin 1 % or dimethicone) followed by thorough combing removes live insects and nits; a noticeable reduction in itching after treatment supports the diagnosis of an infestation.
A systematic approach can be applied:
- Examine hair under good lighting or a magnifying lens. • Look for firmly attached, oval nits close to the scalp. • Observe whether flakes detach easily or remain stuck.
- Assess itching intensity and timing. • Mild, occasional itching → more consistent with flaking. • Persistent, worsening itching after warmth → suggestive of parasites.
- Perform a “wet comb” test. • Wet hair, apply conditioner, comb with a fine‑toothed lice comb. • Presence of live insects or nits confirms infestation.
- Apply appropriate treatment and re‑evaluate after 7–10 days. • Reduction of symptoms validates the initial assessment.
Laboratory confirmation is rarely required, but a dermatologist can perform a scalp scraping for microscopic examination if uncertainty remains. Accurate identification prevents unnecessary medication and ensures effective eradication of the correct condition.