Hair casts and nits - differentiating using dermoscopy

Feroze Kaliyadan¹ , Karalikkattil T Ashique²

¹ Department of Dermatology, College of Medicine, King Faisal University, Al Hasa, Kingdom of Saudi Arabia
² Department of Dermatology, KIMS Al Shifa Hospital and Research Center, Perinthalmanna, Kerala, India

Correspondence Address:
Feroze Kaliyadan
Department of Dermatology, College of Medicine, King Faisal University, Al-Hasa Campus, Al Hasa
Kingdom of Saudi Arabia

A 10-year-old female patient presented to us with complaints of itching of the scalp. Her mother had noticed lice on the scalp. A clinical diagnosis of pediculosis capitis was made. Dermoscopy showed nits attached to the hair shaft [Figure - 1].

Figure 1: Viable ovoid nit containing the embryo attached to the hair shaft with a tubular cast – Polarized dermoscopy, 10X, Dermlite foto II pro attached to Canon 650D single-lens reflex camera

Another 12-year-old female patient presented with complaints of itching and scaling over the scalp. A clinical diagnosis of seborrheic dermatitis was made. Dermoscopy of the hair shaft revealed multiple hair casts [Figure - 2].

Figure 2: Multiple peripilar casts appearing as irregular, amorphous white structures. Polarized dermoscopy 10X, Dermlite foto II pro attached to Canon 650D single-lens reflex camera

Dermoscopy can be a useful tool to differentiate nits from hair casts. Nits appear as ovoid structures attached to the hair shaft with a tubular cast. Viable nits show the embryo within, whereas hatched nits appear translucent and empty. Peripilar keratin casts or hair casts, sometimes called “pseudo-nits,” on dermoscopy show bizarre, irregular-shaped and amorphous white structures [Figure - 2].

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.