Head lice eggs, known as nits, are a sign of an active or recent infestation, often detected using a specialized fine-toothed comb. These tiny specks are easily confused with common hair debris like dandruff, lint, or product buildup. Learning how to identify the specific characteristics of nits caught on a comb is the most reliable way to confirm their presence and determine the appropriate treatment steps.
Identifying Nits by Size and Appearance
Nits are minuscule, teardrop-shaped objects laid by the female louse, about the size of a poppy seed. When first laid, they appear translucent or clear, making them difficult to see against the hair shaft. As the embryo develops, the nit darkens to a yellowish-white, beige, or light brown color.
A key physical property is their location on the hair shaft, as the female louse glues them where the temperature is optimal for incubation. Viable nits are nearly always found very close to the scalp, typically within four to six millimeters (about 1/4 inch) of the skin. Specks found farther down the hair shaft are either empty shells or non-viable eggs, but still confirm a past infestation.
The Key Test Distinguishing Nits from Debris
The most important feature that sets a nit apart is the powerful, waterproof biological cement used to attach it to the hair. This adhesive creates a bond so strong that the nit cannot be simply brushed or shaken away. Common debris, such as dandruff or hairspray residue, moves easily when you attempt to slide it along the hair strand.
To perform the definitive check, try to remove the speck by sliding it with your fingers or by using the fine teeth of the comb. If the speck slides off effortlessly or flakes away, it is most likely dandruff, a hair cast, or product residue. A genuine nit will feel firmly stuck, requiring significant effort or a scraping action with a fingernail or the comb’s teeth to dislodge it from the hair shaft. This distinct adherence is the single most reliable factor for identification.
Hair casts are white, cylindrical sheaths that encircle the hair, but they slide along the hair strand more easily than a nit. The oval, teardrop shape of the nit, combined with its strong cement bond and close proximity to the scalp, provides confirmation. Focusing on the adherence test helps avoid mistaking everyday particles for a true infestation.
What to Do Once Nits Are Confirmed
Finding nits, even without seeing live lice, indicates an active or very recent infestation. The presence of nits means there is a high potential for them to hatch into nymphs, which continues the life cycle. Therefore, prompt action is recommended to stop the cycle.
A full head check of all household members is important, as head-to-head contact is the primary way lice spread. Consult a pharmacist or healthcare provider to discuss treatment options. These typically involve specialized insecticidal products or the thorough, repeated process of wet-combing with a nit comb. A single treatment is often insufficient because most products do not kill all the eggs, requiring a follow-up treatment to catch newly hatched lice.