Biomedical Ephemera, or: A Frog for Your Boils

“Harlequin Fetus”

The fact that this infant is noted to be 8 months old in this photograph is indicative of a form of ichthyosis other than Harlequin-type. Prior to the 1950s, there were only a small handful of cases with that syndrome that survived beyond half a year, and prior to the invention of Isoretinoin (Isotrex/Accutane) in the early 1980s, there were no cases that survived beyond their late-childhood years.

At birth and in infancy, severe lamellar ichthyosis has the potential to appear very similar to Harlequin-type ichthyosis, but with thinner “scales” and cracked tiles of skin. They’re also both autosomal recessive genetic disorders. Despite their similar presentations, the various forms of lamellar ichthyosis are due to genes which cause proliferative hyperkeratosis (creating and shedding keratin at a much higher rate than normal), and Harlequin-type ichthyosis is due to a combination of proliferative and retentive hyperkeratosis - that is, they both create keratinized skin layers much too fast, but they don’t shed them as fast as they’re created.

Textbook of Pediatrics. Emil Feer, 1900.