Medical Pearl: Stereomicroscopy is a useful method to examine hair shaft anomalies

Abstract

A stereomicroscope (STM) is an optical device with two independent oculars that: (1) does not invert the image; and (2) allows us to examine the surface in natura with a magnification up to 80 times. It is widely used in criminal justice, geology, and botanic research. Hair shaft anomalies have, as gold standard for diagnosis, scanning electron microscopy (SEM), which shows surface changes, if necessary with very high magnifications. Because of its high costs, SEM is not always available. We compared the possibility of STM to establish the diagnosis of hair shaft changes with SEM. For that we examined the same hairs with the two techniques. After being photographed under STM, they were set in a stub, metalized, and examined with SEM. We used a hair of pili canaliculi, (Fig 1, A), one hair with two nodules of trichorrhexis nodosa (Fig 1, B), one with a lesion of piedra alba (Fig 1, C ), and a hair with torsion (Fig 1, D). In all of them the typical alterations could be seen by STM and SEM. Although very high magnifications are possible only with SEM, STM can easily identify hair changes, a simple technique that can be used to diagnose hair diseases.