Harlequin-type ichthyosis (also harlequin ichthyosis, ichthyosis congenita, or keratosis diffusa fetalis), a skin disease, is the most severe form of congenital ichthyosis, characterized by a thickening of the keratin layer in fetal human skin. In sufferers of the disease, the skin contains massive, diamond-shaped scales, and tends to give off a reddish color. In addition, the eyes, ears, mouth, and other appendages may be abnormally contracted. The scaly keratin greatly limits the child’s movement. Because the skin is cracked where normal skin would fold, it is easily pregnable by bacteria and other contaminants, resulting in serious risk of fatal infection.

Sufferers are known as harlequin fetuses, harlequin babies, or harlequins.

The harlequin-type designation comes from both the baby’s apparent facial expression and the diamond-shape of the scales (resembling the costume of Arlecchino), which are caused by severe hyperkeratosis. The disease can be diagnosed in the womb by way of fetal skin biopsy or by morphologic analysis of amniotic fluid cells obtained by amniocentesis. In addition, doctors can now usually recognize common features of the disease through ultrasound.

Now take a look at the picture and imagine it screaming. Now I DARE you to have a good night’s sleep.