What is Aplasia Cutis Congenita?
Aplasia cutis congenita (ACC) is a rare condition present from birth where the skin is missing in some places. This absence can extend to the deeper layers of the skin or even the fatty tissue underneath. The cause of ACC is generally unclear, but it’s likely to be because of problems in skin development before the baby is born. The condition might result in a single area of missing skin or several, and these can be anywhere on the body, though most commonly they occur on the top of the head. ACC is divided into different types, some of which are linked to skin conditions that a baby is born with.
In most cases, the missing skin patches tend to heal by themselves, but sometimes there may be need for further medical checks. This is especially true if the location and other features of the missing skin suggest there might be other abnormalities in the body’s soft tissues, which could have serious health implications.
In 1986, a classification system for ACC was proposed and is still used today. This system is made into nine groups, ranging from ACC seen on the scalp without other anomalies to ACC linked with different kind of birth defects or due to specific causes during pregnancy. Knowing the group helps doctors plan for better treatment.
What Causes Aplasia Cutis Congenita?
The cause of ACC, or Aplasia Cutis Congenita, is believed to be a combination of genetics and external factors. Accidents in the womb, exposure to harmful chemicals like methimazole, infections during pregnancy, physical trauma, and birth defects can contribute to ACC.
Until recently, scientists could not pinpoint a specific gene involved in ACC. However, new research suggests that the BMS1 gene could hold a key role.
Additionally, ACC is known to appear alongside several genetic syndromes. For example:
1. Adams-Oliver syndrome involves ACC on the scalp, a defect in the skull, a kind of skin disorder called cutis marmorata telangiectatica, limbs defects, and heart anomalies.
2. Bart syndrome includes ACC on the lower limbs and a skin condition called epidermolysis bullosa.
3. Setleis syndrome is characterized by ACC on both sides of the forehead and a face shape referred to as “leonine” or lion-like.
Risk Factors and Frequency for Aplasia Cutis Congenita
ACC, or Agenesis of the Corpus Callosum, is a rare condition that a person is born with. It’s not very common. In fact, out of every 10,000 births, only about 1 to 3 babies will have this condition. There’s no evidence to suggest that this condition is more common in a specific gender or cultural group. Typically, these lesions are identified at birth, but because they often don’t cause any symptoms, it can be several months before a person with ACC is checked by a doctor.
Signs and Symptoms of Aplasia Cutis Congenita
ACC, also known as Aplasia Cutis Congenita, can show up differently at birth. It could look like a sore, an ulcer, a defect covered by membrane, or a scar, which indicates healing happened inside the womb. In about 70% of the cases, there’s just one lesion and it’s usually on the scalp. However, multiple lesions can also appear on the face, trunk, and limbs. The size of these lesions can range from a few millimeters to several centimeters. If there’s no underlying issue, an ACC lesion will gradually decrease in size and eventually look like a scar.
Testing for Aplasia Cutis Congenita
About 37% of cases of ACC, or aplasia cutis congenita, can be linked to other underlying medical conditions like bone defects, blood vessel abnormalities, or nervous system malformations. So, if a doctor suspects ACC, they might use imaging techniques to get a better look at the affected area.
There are a few signs that doctors might look for. These include a defect on the top of the head, a ring of hair around a birthmark, or certain types of skin discolorations. All of these can be signs of problems with the brain or central nervous system. However, smaller skin defects that occur on the scalp are less likely to be linked to underlying medical conditions and they usually heal themselves within a few months. For these cases, doctors might choose to just monitor the area without doing any imaging.
For larger, open wounds, an ultrasound can be a good way to check for damage without causing the child too much discomfort. If the ultrasound shows anything unusual, a doctor might then recommend an MRI. This kind of imaging can give a much clearer picture of the affected area, but it does have downsides. It’s more expensive than an ultrasound, and the child usually needs to be sedated, which isn’t ideal for a first check-up.
If the wound looks infected or the skin around it is red, a doctor might recommend some lab tests. These could include a complete blood count, blood cultures to check for bacteria, and a wound culture to identify any infection in the sore.
Treatment Options for Aplasia Cutis Congenita
Treatment for patients with ACC, or skin wounds, depends on the wound’s size and whether there’s additional damage under the wound. For small wounds that are less than 4 cm and don’t have any additional issues, it’s suggested to clean them daily and apply an antibacterial ointment until the wound is fully healed. These small wounds usually heal within a few weeks or months, leaving a thin, hairless scar.
However, larger wounds bigger than 4 cm often have underlying issues and are at a higher risk for complications like bleeding, blood clots, and infection. To prevent these complications, it’s recommended to have them surgically repaired as soon as possible. Skin grafts (transplanting skin from one area to another) or flap techniques (moving skin with its blood supply from a nearby area) are often used because these wounds can be several centimeters large.
What else can Aplasia Cutis Congenita be?
ACC, a type of skin condition, can often be identified through a detailed medical examination. However, it may look like other conditions that show the same symptoms at birth.
One such condition is a meningocele – a serious condition where a sac filled with fluid protrudes from the central nervous system (CNS). This often appears as a skin or membrane-covered bump, usually on the scalp. Using imaging techniques like an MRI or a CAT scan, doctors can identify a connection to the CNS, confirming a meningocele.
ACC can also resemble a congenital dermoid cyst – a type of benign tumor that’s present at birth – although ACC typically appears more translucent.
It’s also important for doctors to check if any monitoring or delivery devices were used during birth. Tools like scalp electrodes and forceps can damage the skin, leaving behind wounds that look similar to ACC.
In some instances, lesions may heal while the baby is still in the womb, appearing as a hairless scar, which could be mistaken for a skin condition known as an epidermal nevus.
Remember, it’s always crucial to consult with healthcare professionals for proper diagnosis and treatment of any symptoms or conditions.
What to expect with Aplasia Cutis Congenita
ACC, when it occurs alone without any underlying condition, can follow a relatively mild path. However, if complications arise, the risk of death can significantly increase, with the estimated mortality rate ranging from 20% to 55% due to severe complications.
The most serious complication of ACC is sagittal sinus bleeding, which often occurs with lesions located nearby on the scalp. An additional complication includes secondary infections of the lesion. This is due to the skin’s protective barrier against germs from the environment being absent or weakened, increasing the risk of skin infections.
These serious infections can further develop into meningitis if they’re not correctly treated. To prevent these risks, immediate management of large scalp lesions, most commonly through surgery, is recommended.
