The Bottom Line

Neurofibromatosis type 1 (NF1) is a genetic condition that often shows up first on the skin as light-brown spots called café-au-lait macules. If your child has 6 or more of these spots (each at least 1.5 cm across), a doctor will want to look closely for NF1. The condition is manageable, but it does need lifelong monitoring because it can affect the eyes, bones, nervous system, and — in some cases — raise cancer risk. The good news: most people with NF1 live full, active lives with proper care.

What Is Neurofibromatosis Type 1 (NF1)?

NF1 is an inherited condition caused by a change (mutation) in the NF1 gene. This gene normally helps control cell growth. When it doesn't work correctly, certain types of benign (non-cancerous) tumors called neurofibromas can grow along nerves and in the skin. NF1 is one of the most common genetic disorders, affecting about 1 in 3,000 people worldwide. It's passed down through families in an "autosomal dominant" pattern — meaning one changed copy of the gene is enough to cause it. About half of all NF1 cases, however, occur in children with no family history at all, the result of a new gene change.

What Are the Skin Signs?

The skin is often the first place NF1 makes itself known. Here are the most common things doctors look for:

  • Café-au-lait spots: Flat, light-brown patches that look like coffee-stained skin. Having 6 or more spots that are at least 1.5 cm (about the size of a dime) is a key diagnostic sign. These are usually present at birth or appear in early childhood.
  • Axillary and inguinal freckling: Small freckles appearing in the armpits or groin — areas not normally exposed to sun — are another hallmark of NF1.
  • Neurofibromas: Soft, rubbery bumps that grow on or just under the skin. They can appear anywhere on the body and tend to increase in number with age. Most are benign.
  • Plexiform neurofibromas: Larger, deeper tumors that may be present at birth. They can grow and sometimes cause disfigurement or press on nearby structures.
  • Lisch nodules: Tiny, harmless growths on the iris (colored part) of the eye, visible only with a special lamp — not a skin sign, but often found during eye exams.

What Else Can NF1 Affect?

NF1 is more than a skin condition. It can affect several body systems, which is why regular check-ups matter:

  • Eyes: Optic nerve gliomas (growths on the nerve connecting the eye to the brain) occur in 15–20% of NF1 patients. Many are asymptomatic, but vision monitoring is important.
  • Bones: Some children develop scoliosis (spine curvature), bone thinning, or other skeletal problems.
  • Brain and learning: Learning disabilities and ADHD are more common in children with NF1. This does not mean intellectual disability — many children with NF1 are intellectually typical.
  • Blood pressure: High blood pressure can occur due to certain tumor types (pheochromocytoma) or kidney artery changes.
  • Cancer risk: NF1 raises the risk of malignant peripheral nerve sheath tumors (MPNST) and a few other cancers. Regular surveillance helps catch any changes early.

How Is NF1 Diagnosed?

Doctors diagnose NF1 using established criteria — a checklist of findings. Your child needs at least 2 of the following:

  • 6 or more café-au-lait spots measuring at least 1.5 cm
  • 2 or more neurofibromas (or 1 plexiform neurofibroma)
  • Axillary or groin freckling
  • Optic nerve glioma
  • 2 or more Lisch nodules in the eyes
  • A distinctive bone problem (sphenoid dysplasia or tibial bowing)
  • A first-degree relative (parent, sibling) with NF1

Genetic testing can confirm the NF1 gene mutation, though it isn't always needed if the clinical signs are clear.

How Are the Skin Findings Treated?

Most café-au-lait spots and neurofibromas don't need treatment. When they cause cosmetic concerns or physical discomfort, options include:

  • Surgical removal: Neurofibromas that bother your child — whether by appearance or by pressing on nerves — can be surgically excised.
  • Newer targeted therapies: Drugs called MEK inhibitors (like selumetinib) have shown real promise in shrinking plexiform neurofibromas and are now FDA-approved for children with NF1.
  • Laser treatments: Some dermatologists use lasers to lighten café-au-lait spots, though results vary.
  • Monitoring: Regular skin exams watch for any neurofibroma that looks like it might be changing or growing rapidly, which could signal malignant transformation.

When to See a Dermatologist

  • Your child has 6 or more café-au-lait spots, especially if they are larger than a dime
  • You notice freckling in the armpits or groin of a young child
  • New or rapidly growing skin bumps appear
  • Any bump becomes painful, changes color, or grows quickly — this needs prompt evaluation
  • You have a family history of NF1 and want your child screened
  • A neurofibroma is causing functional problems (pressing on a nerve or nearby organ)

Frequently Asked Questions

Does NF1 mean my child will definitely get cancer?

Not necessarily. While NF1 does raise the lifetime risk of certain cancers — particularly malignant peripheral nerve sheath tumors — most people with NF1 never develop cancer. Regular surveillance is key because early detection leads to better outcomes. Your child's care team will set up a monitoring plan tailored to their specific situation.

My child has a few café-au-lait spots — does that mean they have NF1?

Not always. Many children have 1 to 3 café-au-lait spots and are perfectly healthy. What raises concern is having 6 or more spots that are at least 1.5 cm wide. Isolated spots without other NF1 features are usually not a sign of the condition. A dermatologist or geneticist can help determine whether further evaluation is needed.

Will neurofibromas keep growing throughout life?

Yes, neurofibromas tend to increase in number and size with age, and they often grow more rapidly during puberty and pregnancy. Most remain benign. Your child's doctor will monitor for any that change in a concerning way, and removal is an option for troublesome tumors.

What kind of doctors should follow my child with NF1?

NF1 is best managed by a multidisciplinary team. This typically includes a dermatologist (skin), neurologist (brain and nerves), ophthalmologist (eyes), and potentially an orthopedist (bones). Many academic medical centers have dedicated NF1 clinics that coordinate all of this care in one place.

  1. Gutmann DH, et al. Neurofibromatosis type 1. Nat Rev Dis Primers. 2017;3:17004.
  2. Evans DG, et al. Birth incidence and prevalence of tumor-prone syndromes. Am J Med Genet A. 2010;152A(2):327–332.
  3. Vaessen M, et al. Selumetinib for plexiform neurofibromas in NF1. N Engl J Med. 2020;382:1430–1442.
  4. National Institutes of Health Consensus Development Conference Statement on NF1. Arch Neurol. 1988;45(5):575–578.

Trusted Resources

Always consult a board-certified dermatologist or your child's physician for personalized medical advice regarding neurofibromatosis and skin care.