Overview
Nevus simplex, commonly referred to as a salmon patch, is a benign vascular malformation often seen in newborns. This birthmark typically appears as pink or red patches on the skin and is most commonly found on the nape of the neck, eyelids, or forehead. Specific types of nevus simplex include stork bites, which are located on the back of the neck, and angel kisses, which appear on the face. These marks are generally harmless and often resolve on their own within the first few years of life.
Causes
Nevus simplex is caused by dilated capillaries near the skin’s surface, leading to increased blood flow in those areas during fetal development. The exact mechanism behind this vascular malformation is not entirely understood, but it is considered a normal variation in newborn skin development.
The formation of these patches occurs due to the dilation of blood vessels under the skin. This increased blood flow to the area results in the characteristic reddish appearance of nevus simplex. This condition is a normal and common occurrence in newborns and does not indicate any underlying pathology.
Symptoms
Nevus simplex presents as flat, pink to reddish-purple patches without well-defined borders. These patches blanch (become pale) when pressure is applied. They are commonly found on the posterior neck, scalp, forehead, eyelids, and glabella. The coloration may intensify when the child cries, gets warm, or engages in physical activity. Stork bites, located on the back of the neck, and angel kisses, found on the face, are specific types of nevus simplex.
The lesions of nevus simplex are usually flat and can vary in size. They are typically non-painful and non-itchy. These patches are most visible during times of increased blood flow, such as when the baby is crying or during physical exertion. Over time, most of these lesions will fade and may disappear entirely by the age of one to two years. However, some may persist into adulthood, especially those located on the nape of the neck.
Diagnosis
Diagnosis of nevus simplex is primarily clinical, based on the appearance of the lesions. These patches are usually visible at birth and are identified by their characteristic pink or red coloration and blanching nature. A thorough physical examination by a healthcare provider is generally sufficient for diagnosing nevus simplex, and no additional testing is typically required.
During the examination, the healthcare provider will look for the typical features of nevus simplex, including the location, size, and color of the lesions. The healthcare provider will also check for the blanching characteristic of these patches by applying gentle pressure to see if the color fades temporarily. This simple clinical assessment is usually adequate for confirming the diagnosis of nevus simplex.
Differential Diagnosis
It is crucial to differentiate nevus simplex from other vascular lesions such as port wine stains (nevus flammeus) and infantile hemangiomas. Port wine stains are persistent, unilateral, and may darken with age, indicating a potential association with genetic syndromes. Infantile hemangiomas are vascular tumors that grow rapidly during infancy and may leave residual marks after regression.
Treatment
Nevus simplex is benign and typically does not require treatment. Most lesions fade significantly by the age of one to two years. For lesions that persist, especially stork bites on the neck, treatment options such as laser therapy can be considered for cosmetic reasons.
Monitoring and Complications
While nevus simplex is generally harmless, it is important to monitor any changes in the lesion’s appearance. If a lesion becomes larger, changes color, or shows signs of swelling, it should be evaluated by a healthcare provider. In rare cases, lesions located in the lumbosacral region may be associated with spinal dysraphism, especially if accompanied by other anomalies such as dimples, sinus tracts, or excess hair growth.
Prognosis
The prognosis for infants with nevus simplex is excellent. Most lesions fade over time and do not cause any health problems. Stork bites may persist into adulthood but are typically covered by hair and do not require treatment.
Long-Term Outlook
For most children, nevus simplex lesions will diminish significantly within the first few years of life. Those that persist, particularly stork bites, are generally considered a cosmetic concern rather than a medical issue. The condition does not pose any long-term health risks.
Complications
While nevus simplex itself is benign, it can sometimes be associated with other conditions. For instance, midline lumbosacral nevus simplex, sometimes called a butterfly-shaped mark, may indicate spinal dysraphism if accompanied by other local skin anomalies. Nevus simplex can also occasionally be observed in infants with genetic syndromes such as Beckwith-Wiedemann syndrome, macrocephaly-capillary malformation syndrome, and others. However, these associations are rare, and the presence of nevus simplex alone does not necessarily indicate these conditions.
Cosmetic Concerns
For lesions that persist into adulthood, particularly on visible areas such as the face or neck, cosmetic treatments like laser therapy can be considered to reduce their appearance. It is important to discuss these options with a dermatologist to understand the potential benefits and risks.
Prevention
There is no known way to prevent the appearance of nevus simplex or other birthmarks. These vascular malformations are a normal occurrence in newborns and are present in a significant proportion of infants.
Outlook / Prognosis
Stork bites and other forms of nevus simplex are harmless and add a unique cosmetic feature to your baby’s appearance. They do not need treatment and pose no threat to your child’s overall health.
It is normal for the color of your child’s stork bite to turn bright pink, red, or purple and become more noticeable when your child cries or gets too warm. If your child’s stork bite grows in size, shape, or turns a different color than normal, visit your child’s healthcare provider for an examination.
Stork bites are generally a benign and self-limiting condition. Most will fade over time, and any residual marks are usually covered by hair or are not prominent enough to cause concern. Parents can be reassured that the presence of nevus simplex does not indicate any underlying health issues and that the condition will likely resolve without the need for medical intervention.
Duration
Stork bites are present at birth and may fade after your child turns one to two years old. The birthmark could last through childhood but will often be present when your child reaches adulthood.
For most children, the appearance of nevus simplex will diminish significantly within the first few years of life. However, some lesions, particularly stork bites, may persist into adulthood. These persistent lesions are typically covered by hair and do not pose any health risks. The duration and persistence of these birthmarks can vary, but they generally do not cause any long-term problems.
When to Seek Medical Advice
If you notice your child’s stork bite changes color to something different than pink, red, or purple, if your child’s birthmark grows in size, or if the skin around the birthmark changes, visit your child’s healthcare provider for an examination.
References
Cleveland Clinic. (n.d.). Stork bite (Nevus simplex). Retrieved March 9, 2025, from https://my.clevelandclinic.org/health/diseases/17845-stork-bite
DermNet NZ. (n.d.). Nevus simplex. Retrieved March 9, 2025, from https://dermnetnz.org/topics/nevus-simplex
Stanford Children’s Health. (n.d.). Birthmarks. Retrieved March 9, 2025, from https://www.stanfordchildrens.org/en/topic/default?id=birthmarks
