Harlequin ichthyosis

Harlequin ichthyosis (also known as harlequin baby, harlequin fetus, or ichthyosis congenita gravior) is one of the most severe forms of congenital ichthyosis, a group of genetic skin disorders. It is caused by mutations in the ABCA12 gene, which encodes a lipid transporter protein essential for normal skin barrier development. Affected infants are born encased in thick, armor-like plates of skin separated by deep red fissures (cracks). The massive thickening of the skin causes severe distortion of facial features, including ectropion (outward turning of the eyelids), eclabium (outward turning of the lips), flattened ears and nose, and restricted movement of the limbs. The rigid skin plates can restrict chest expansion, potentially compromising breathing. Harlequin ichthyosis is apparent at birth and historically was associated with very high neonatal mortality. However, advances in neonatal intensive care and the early use of oral retinoids (such as acitretin) have significantly improved survival rates. Treatment in the neonatal period focuses on maintaining hydration, preventing infection, temperature regulation, nutritional support, and careful skin care including emollients and gentle debridement of the thickened skin. Surviving infants typically shed the thick plates within weeks and develop a phenotype resembling severe congenital ichthyosiform erythroderma, with persistent generalized redness and scaling of the skin that requires lifelong management. Ongoing care includes regular application of emollients and keratolytic agents, monitoring for skin infections, ophthalmologic care for persistent ectropion, and psychosocial support. Long-term retinoid therapy may be continued to help manage the scaling, though this requires careful monitoring for potential side effects including effects on bone growth and liver function.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Harlequin ichthyosis