What are the other Names for this Condition? (Also known as/Synonyms)

• ACC (Aplasia Cutis Congenita)
• Congenital Scalp Defect
• Congenital Ulcer of Newborn

What is Aplasia Cutis Congenita? (Definition/Background Information)

• Aplasia Cutis Congenita (ACC) is a rare skin condition present at birth in which certain layers of the skin are absent from one or multiple areas on the newborn’s body (most commonly involving the scalp)
• The cause of Aplasia Cutis Congenita is unknown; though, evidence supports the cause to be a combination of several factors including genetics, exposure to toxins during pregnancy, and intrauterine trauma
• A healthcare provider typically diagnoses Aplasia Cutis Congenita upon examination of a newborn’s skin for abnormalities (missing skin layers). The affected area appears transparent and thin, and one is often able to see underlying structures through the skin
• The treatment of Aplasia Cutis Congenita involves a ‘wait and watch’ approach, since many cases are known to resolve by themselves. However, if necessary, the use of medications and surgery may be considered
• The prognosis of Aplasia Cutis Congenita is generally very good in the long-term. However, those who have additional (or other underlying) disorders may present complications. In such cases, the prognosis may be adversely affected

Who gets Aplasia Cutis Congenita? (Age and Sex Distribution)

• Aplasia Cutis Congenita is a rare disorder, affecting about 3 in 10,000 newborns
• Approximately, 500 cases have been recorded in the medical literature so far
• Individuals of all races/ethnicities and both male and female genders are susceptible to ACC

What are the Risk Factors for Aplasia Cutis Congenita? (Predisposing Factors)

The risk factors associated with development of Aplasia Cutis Congenita include:

• Exposure to teratogens (agents that increase the likelihood of birth defects) during pregnancy 
• A family history of the condition
• Decreased blood flow to the affected area due to poor vasculature
• Intrauterine trauma during pregnancy

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Aplasia Cutis Congenita? (Etiology)

The exact cause of Aplasia Cutis Congenita is not fully-understood. The formation of lesions characteristic of ACC is complex. It is related to the failure of multiple biological mechanisms. Research suggests that the condition may result from an interaction of multiple factors, including:

• Exposure to teratogens: Teratogens are defined as substances that increase the risk of a birth defect. Some examples of known teratogens include:
  • Methimazole and carbimazole, which may be used to treat hyperthyroidism
  • Misoprostol, which may be used for treatment of stomach ulcers, for inducing labor, and to stem post-partum bleeding
  • Valproic acid that may be used in the treatment of seizures
• A defect leading to decreased development of skin blood vessels
• Abnormal neural tube development: A neural tube in the developing embryo forms the central nervous system. A defect in this tube develops early in pregnancy, which may result in causation of the condition
• Trauma during pregnancy or prolonged pressure against the interior uterine wall
• Genetic factors: The exact mutations that are involved in ACC are unknown presently. The condition can run in families, both in an autosomal dominant and autosomal recessive manner

Therefore, limited clinical data indicates that there is no singular root cause for Aplasia Cutis Congenita development. But, it may result instead from several factors listed above.

Autosomal dominant pattern of inheritance: In this type of inheritance, a single copy of the mutated gene is sufficient to cause the condition. Thus, having a single parent with the condition may cause ACC in children.

Autosomal recessive pattern of inheritance: In this type of inheritance, an individual must possess both copies of a gene in a defective form, in order for the condition to manifest itself. The affected individual inherits one defective gene copy from each parent. The parents are carriers of the condition, and remain typically unaffected.

What are the Signs and Symptoms of Aplasia Cutis Congenita?

The signs and symptoms of Aplasia Cutis Congenita vary from one individual to another. While the presence of the ACC lesion at birth (lesion on the scalp) is the key symptom of the condition, additional features that may be noted include:

• Malformation of the spinal cord (neural tube defects)
• Congenital localized absences of skin; poorly-formed or total absence of skin in focal areas
• Skin ulcers (long-term sores)
• Abnormal bone mineral density
• Facial palsy resulting in an inability to control muscles of the face
• Extended bleeding times (a bleeding time is a test performed to assess platelet function)

How is Aplasia Cutis Congenita Diagnosed?

The diagnosis of Aplasia Cutis Congenita is made by identifying characteristic lesions of the condition, on the scalp, trunk, arms, or legs. After this identification, a healthcare provider is likely to further characterize the condition by: 

• A complete physical examination and an assessment of symptoms
• An evaluation of the affected individual’s family medical history
• Bleeding test, where the skin is superficially incised at specific locations to assess bleeding time. The bleeding time may vary in regions of abnormal skin formation, when compared to normal skin formation
• Examination of the affected areas for bacterial infections or signs of other related conditions

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Aplasia Cutis Congenita?

Complications of Aplasia Cutis Congenita are unlikely, but if they do develop, they may include:

• Hemorrhage
• Formation of clots
• Infection of the affected areas
• Meningitis (swelling of tissues surrounding areas of the brain and spinal cord)
• Complications related to the lesions, due to decreased protective layers of the skin, such as increased susceptibility to injury following a minor trauma

How is Aplasia Cutis Congenita Treated?

The following are some treatment options for Aplasia Cutis Congenita:

• Basic observation and infection prevention, using ointments, while allowing the skin lesions to heal on their own
• Administration of antibiotics (for infections in the affected area, if any)
• Surgical repair of larger lesions that are less likely to heal on their own

How can Aplasia Cutis Congenita be Prevented?

The etiology/cause of Aplasia Cutis Congenita is not fully understood, and therefore, comprehensive preventative measures are yet to be developed.

• However, avoiding the teratogens during pregnancy is advisable, under medical supervision
• If there is a family history of the condition, then genetic counseling may help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as Aplasia Cutis Congenita

Regular medical screening at periodic intervals with tests and physical examinations are strongly recommended.

What is the Prognosis of Aplasia Cutis Congenita? (Outcomes/Resolutions)

• The prognosis of Aplasia Cutis Congenita is very good, since in many cases, the condition only requires conservative treatment for permanent resolution
• In case of complications or the appearance of other related conditions, the prognosis may be affected

Additional and Relevant Useful Information for Aplasia Cutis Congenita:

Aplasia Cutis Congenita is identified as an absence of layers of skin, which may or may not also include the absence of structures such as bone or other tissue that exist underneath the skin layers.