Signs and symptoms
Newborns with harlequin-type ichthyosis present with thick, fissured armor-plate hyperkeratosis. Sufferers feature severe cranial and facial deformities. The ears may be very poorly developed or absent entirely, as may the nose. The eyelids may be everted (ectropion), which leaves the eyes and the area around them very susceptible to infection. Babies with this condition often bleed during birth. The lips are pulled back by the dry skin (eclabium).Joints are sometimes lacking in movement, and may be below the normal size. Hypoplasia is sometimes found in the fingers. Polydactyly has also been found on occasion. In addition, the fish mouth appearance, mouth breathing, and xerostomia place affected individuals at extremely high risk for developing rampant dental decay.Patients with this condition are extremely sensitive to changes in temperature due to their hard, cracked skin, which prevents normal heat loss. The skin also restricts respiration, which impedes the chest wall from expanding and drawing in enough air. This can lead to hypoventilation and respiratory failure. Patients are often dehydrated, as their plated skin is not well suited to retaining water. Cause
Harlequin-type ichthyosis is caused by a loss-of-function mutation in the ABCA12 gene. This gene is important in the regulation of protein synthesis for the development of the skin layer. Mutations in the gene cause impaired transport of lipids in the skin layer and may also lead to shrunken versions of the proteins responsible for skin development.
Dehydroepiandrosterone (DHEA) produced from the fetal adrenal gland and androgen production from neonatal testicles may also stimulate sebum production from sebaceous glands.The role of genetics is unclear but a positive family history supports association with neonatal acne.Some researchers suggest the role of Malassezia colonization causing hypersensitivity reactions in skin but this tends to be linked to neonatal cephalic pustulosis more so than neonatal acne. Diagnosis
A work up is suggested in cases of severe acneiform eruptions or with signs of growth abnormalities to rule out potential endocrine diseases, tumor formation, or gonadal development abnormalities. A referral to a pediatric endocrinologist may be warranted. Differential Diagnosis
Other causes of acneiform eruptions such as those induced by the use of topical products like creams, ointments and shampoos on the skin are often ruled out before diagnosis. Maternal medications like lithium and high dose corticosteroids may also induce formulation of pustules in newborns and can be assessed with a thorough family history. Likewise, newborns can be assessed for infection whether bacterial, fungal or viral in nature. Erythema toxicum neonatorum, neonatal cephalic pustulosis, transient neonatal pustular melanosis, folliculitis, miliaria and milia are often ruled out before diagnosis.Some experts consider neonatal cephalic pustulosis (NCP) a form of neonatal acne while others do not. NCP presents with facial papules and pustules but no comedones. NCP has been linked to Malassezia colonization, a normal yeast found on skin, but inconsistent patterns of positive colonization and NCP suggests that Malassezia hypersensitivity reactions in susceptible newborns are the cause of the acneiform eruptions rather than colonization itself.