What Is Aplasia Cutis Congenita?

Children born with the condition are most often missing skin on their scalp

Child skin disorder. Credit: Orlando Sentinel / Contributor / Getty Images

Aplasia cutis congenita is a skin disorder that causes children to be born with a missing patch of skin. Aplasia cutis congenita may occur by itself or as a symptom of other disorders such as Johanson-Blizzard syndrome and Adams-Oliver syndrome. Aplasia cutis congenita may be inherited or occur without any family history of the condition. The disorder affects both males and females of all ethnic backgrounds and occurs in about 1 in 10,000 births.


Researchers aren't sure which genes cause aplasia cutis congenita, but they suspect the genes that affect skin growth may be mutated. In some cases, the condition may be caused by exposure to methimazole –– a drug used to treat hyperthyroidism. Other cases may also be caused by a virus or any injury to the baby during pregnancy. If the condition is inherited, it is usually only passed down by one parent. 

Signs and Symptoms of the Disease

A child born with aplasia cutis congenita will be missing a patch of skin, usually on the scalp (70-percent of individuals). Missing patches can also occur on the trunk, arms, or legs. Most children only have one missing patch of skin; however, multiple patches can be missing. The affected area is usually covered with a thin transparent membrane, is well-defined, and is not inflamed. The open area may look like an ulcer or an open wound. Sometimes the missing patch of skin heals before the child is born.

The missing patch is usually round but may also be oval, rectangular, or star-shaped. How large the patch is, varies.

If aplasia cutis congenita occurs on the scalp, there may be a defect of the skull underneath the missing patch. In this case, there is often distorted hair growth around the patch, known as the hair collar sign.

If the bone is affected, there is an increased risk of infections. If the bone is severely compromised, the covering of the brain may be exposed and the risk of bleeding increased. 

Getting an Aplasia Cutis Congenita Diagnosis 

Aplasia cutis congenita is diagnosed based on the appearance of the infant’s skin. Defects can be noticed immediately after birth. If the patch healed before the child was born, hair will be missing from the affected area. No specific laboratory tests are needed to diagnose the condition. Very large scalp defects, especially those with the hair collar sign, should be investigated for possible underlying bone or soft tissue defects.

Treating Aplasia Cutis Congenita

Most often, the only treatment required for aplasia cutis congenital is a gentle cleansing of the affected area and the application of silver sulfadiazine to prevent the patch from drying out. Most affected areas will heal on their own over several weeks, resulting in the development of a hairless scar. Small bone defects also usually close on their own within the first year of life.

Surgery can usually be avoided unless the missing area of skin is large, or several areas of the scalp are affected.

Crowe, M. (2005). Aplasia cutis congenita. eMedicine
National Organization for Rare Disorders. Aplasia Cutis Congenita

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