An infant with annular alopecia

Issue: December 2011

A 4-month-old male presents to your clinic with a history of scalp alopecia present since birth.

The alopecia has become more noticeable as the surrounding hair has grown around the involved area. The parents deny any obvious trauma during labor or delivery, and no instrumentation was used to assist with the delivery. However, the mother recalls premature rupture of membranes and laboring for several hours. For several days after delivery, there was notable scalp swelling, consistent with a hemorrhagic caput succedaneum. The parents said the alopecia follows a distribution similar to the scalp swelling noted at birth.

Marissa Perman, MD

On physical exam, the infant is thriving and appears well. There is focal scalp alopecia in a circular pattern along the occipital scalp. The remainder of the physical exam is unremarkable.

What is the most likely etiology?

Diagnosis: Halo scalp ring

Halo scalp ring is a unique form of alopecia, usually non-scarring, associated with caput succedaneum or severe scalp edema at or shortly after birth. It is more common in infants born to primigravid women. Other associated findings include prematurity, premature and/or prolonged rupture of membranes, and prolonged labor. Ongoing pressure by the cervix, uterus and vaginal wall on the presenting part, usually the scalp, is thought to cause pressure necrosis and leads to this type of alopecia.

Halo scalp ring is not associated with neurologic or other systemic findings, and further workup is not indicated. A detailed history of the labor and delivery will aid in making the diagnosis. The differential diagnosis includes aplasia cutis congenita when seen in the setting of scarring. However, the annular nature would be unlikely in aplasia cutis congenita.

Halo scalp ring is a unique form of annular alopecia involving the vertex of the scalp seen at or shortly after birth, usually in the setting of caput succedaneum.

Observation and reassurance is the most appropriate management in most cases. The alopecia appears to be temporary in many patients, and the hair re-grows in time. In some cases, the alopecia may take several years to improve. If the alopecia or scarring is cosmetically unacceptable, tissue expanders and surgical excision may be considered.

Halo scalp ring is a unique form of annular alopecia involving the vertex of the scalp seen at or shortly after birth, usually in the setting of caput succedaneum. Physicians should be aware of this distinct entity, and in most cases, provide reassurance to families.

Caput succedaneum is a common finding related to birth trauma and is seen in prolonged or difficult labor leading to swelling and red blood cell extravasation into the subcutaneous tissues above the periosteum. It tends to cross the midline, as well as suture lines, and usually resolves within a few days without sequelae. If severe, it may be associated with hemorrhage, skin necrosis or a frank skull fracture.

Pressure necrosis associated with caput succedaneum may cause hypoxic-ischemic injury of the tissue, including the hair follicles, which can lead to alopecia. The alopecia seen with caput succedaneum usually follows an annular pattern involving the vertex of the scalp, akin to the shape of the pelvis, and may range from a few to several centimeters. Rarely, if the necrosis is severe, the skin may ulcerate or develop crusting, which can lead to permanent scarring of the skin in the shape of a scalp ring with persistent alopecia.

For more information:

Martín JM. Pediatr Dermatol. 2009;26:706-708.

Neal PR. Pediatr Dermatol. 1984;2:52-54.

Prendiville JS. Arch Dermatol. 1987;123:992-993.

Tanzi EL. Arch Pediatr Adolesc Med. 2002;156:188-190.

Marissa J. Perman, MD, is a pediatric dermatology fellow at The Children’s Hospital of Philadelphia. Disclosure: Dr. Perman reports no relevant financial disclosures.

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