As the most severe form of congenital ichthyosis, harlequin ichthyosis is an extremely painful, debilitating skin condition where the keratin layer on the epidermis thickens, creating a scaly cluster of red, irritated, dry patches of skin all over the body. In addition, from birth, the eye lids, ears, penis, and other extremities are contracted inward; in many cases, it is common for the eye lids of harlequin ichthyosis babies to be inverted (turned inside out) to reveal the red, internal skin of the eye lids.
Many harlequin patients suffer from bacterial infections due to the presence of dry, cracked skin in areas where normal skin would have crevices and would be easily able to fold and bend; the dry, cracked skin all over the body of harlequin patients allows for airborne contaminants, and contaminants by direct contact, to seep into their skin via their open wounds.
In many cases, counteracting the effects of this disorder would involve spending hours soaking in a warm bath, to loosen/soften the layer of dry, damaged skin cells, and spending even more time moisturizing their harsh, dry layers of skin. They may also face difficulty with preventing infection, and often with becoming dehydrated, noting that harlequin patients are without the ability to sweat and maintain homeostasis.
This disorder is usually present at birth because it involves a mutation in the gene that accounts for the protein ABCA12.