Aplasia cutis congenita
What is aplasia cutis congenita?
Aplasia cutis congenita is a condition in which a newborn child is missing skin from certain areas.
How do you get aplasia cutis and who is at risk?
It is not yet fully known why aplasia cutis occurs but the following factors may be involved.
- Genetics: aplasia cutis may be seen in association with other congenital skin defects such as epidermal naevi
- Infection during pregnancy, such as varicella or herpes simplex
- Teratogens (drugs or chemicals causing birth deformities)
- Defect in skin development in the embryo/fetus
- Amniotic bands due to early rupture of amniotic membranes
- Aplasia cutis affecting the limbs may be associated with the death of a twin fetus (papyreous fetus).
Aplasia cutis is rare and no particular race or sex is at greater risk.
What are the clinical features of aplasia cutis?
In about 70% of cases, aplasia cutis affects the scalp lateral to the midline, but lesions may also occur on the face, trunk, or limbs, sometimes symmetrically.
- The areas of skin loss or ulceration vary in size from 0.5 cm to 10 cm.
- The defects are non-inflammatory and are well demarcated.
- Superficial aplasia cutis involves only the epidermis (upper layers of skin). Shallow defects usually heal over before the child is born, leaving a scar.
- Deeper defects can extend through the dermis, subcutaneous tissue, and rarely periosteum, skull, or dura.
- Aplasia cutis may partially heal before delivery and appear as a hairless, atrophic, membranous, parchmentlike or fibrotic scar.
- Membranous aplasia cutis is a flat, white membrane overlying a defect in the skull. Distorted hair growth, known as the hair collar sign, is a marker for an underlying cranial defect such as encephalocoele, meningocoele, and brain tissue outside the skull.
- A rare bullous variant of aplasia cutis congenita has been reported.
What is the differential diagnosis for aplasia cutis?
Other conditions that should be considered include:
- Epidermolysis bullosa
- Neonatal herpes simplex infection
- Transient bullous dermolysis of the newborn
- Birth trauma
- Setleis syndrome: this is bitemporal aplasia cutis congenita with other facial cutaneous abnormalities.
What treatments are available for aplasia cutis?
Small areas of aplasia cutis usually heal spontaneously over time. To prevent infection gentle cleaning and bland ointments may be used. If infection occurs, antibiotics can be used.
Larger lesions or multiple scalp defects may require surgical repair; sometimes skin or bone grafting may be required.
What are the complications of aplasia cutis?
Complications of aplasia cutis rarely occur but may include:
- Arterial bleeding
- Secondary wound infection
- Sagittal sinus thrombosis.
- Infection of the brain leading to death.