Aplasia cutis congenita is a condition in which there is congenital (present from birth) absence of skin, with or without the absence of underlying structures such as bone. It most commonly affects the scalp, but any location of the body can be affected. While most people with aplasia cutis congenita have no other abnormalities, some people have congenital malformations involving the cardiovascular (heart), gastrointestinal, genitourinary, and central nervous systems.
It can be associated with Johanson-Blizzard syndrome, Adams-Oliver syndrome, trisomy 13, and Wolf-Hirschhorn syndrome. It can also seen with exposure to methimazole and carbimazole in utero. This dermatological manifestation has been linked to Peptidase D haploinsufficiency and a deletion in Chromosome 19.
- Scalp defect
- Simian crease
- Sparse scalp hair
- Skull defect
- Spinal dysraphism
- lack skin (and therefore hair)
- Underlying bone may be missing as well as the skin
- Affected structures and other organs may be seen through the transparent membrane
The cause of this condition is unclear and appears to be multifactorial (many different factors appear to play a role); contributing factors may include teratogens, genes, trauma, and compromised skin perfusion. Factors that may contribute include genetic factors; teratogens (exposures during pregnancy that can harm a developing fetus) such as methimazole, carbimazole, misoprostol, and valproic acid; compromised vasculature to the skin; and trauma. Some cases may represent an incomplete or unusual form of a neural tube defect. Familial cases of aplasia cutis congenita have been reported. Cases that appear to be genetic may be inherited in an autosomal dominant or autosomal recessive manner.
The long-term outlook (prognosis) for people with aplasia cutis congenita is usually excellent. If the condition is associated with other abnormalities or malformations, the prognosis then depends on the nature and severity of the other condition(s).
Major complications of aplasia cutis congenita are rare, but can include hemorrhage, secondary local infection, meningitis, or sagittal sinus thrombosis. Larger affected areas associated with underlying bony defects can cause death due to central nervous system infection, or hemorrhage from the sagittal sinus. Complications can also result from associated abnormalities or malformations, when present.
The management of aplasia cutis congenita of the scalp is controversial; both surgical and conservative treatment modalities have their proponents and opponents. The decision to use medical, surgical, or both forms of therapy in aplasia cutis congenita depends primarily on the size, depth, and location of the skin defect.
Local therapy includes gentle cleansing and the application of bland ointment or silver sulfadiazine ointment to keep the area moist. Antibiotics may be utilized if overt signs of infection are noted. In many cases, other treatment is not necessary because the erosions and the ulcerations almost always heal on their own. Recently, a variety of specialized dressing materials have been developed and used.
Surgical repair is not usually indicated if the defect is small. Recovery is generally uneventful, with gradual epithelialization and formation of a hairless, atrophic scar over several weeks. Small underlying bony defects usually close spontaneously during the first year of life. Surgical repair of large or multiple scalp defects may require excision with primary closure, if feasible, or the use of tissue expanders and rotation of a flap to fill the defect. On occasion, skin and bone grafts may also be required.