Congenital Dermal Melanocytosis

Overview

Congenital dermal melanocytosis is a type of birthmark. The long name simply means a patch of extra colour in the deeper layer of a baby's skin that is there from birth. Most people know it as 'Mongolian spots' or 'slate grey patches'. The marks are flat, smooth, and blue-grey or blue-black, a bit like a bruise. They are not bruises, they do not hurt, and they are not a sign that anything is wrong. The colour comes from melanocytes (the cells that make skin pigment) sitting deeper in the skin than usual, which is why the patch looks blue-grey through the skin rather than brown.

Very common. It is one of the most common birthmarks in the world. In some groups it is seen in more than 9 out of 10 newborns.

It is most common in babies with darker skin, including babies of African, Asian, South Asian, Middle Eastern, Hispanic, Pacific Islander and Indigenous American heritage. It can affect babies of any background, but it is much less common in babies with very fair skin.

Symptoms

Common symptoms

• One or more flat patches on the skin, blue-grey, slate grey, or blue-black in colour
• Patches are smooth, with the same feel and texture as the skin around them
• Edges are usually blurry and uneven rather than sharp
• Size can range from a small coin-sized spot to a patch covering a large area
• Most often found on the buttocks and lower back, and sometimes on the shoulders, arms, legs or elsewhere
• No pain, no itching and no tenderness when touched
• The patch does not change when you press on it

Symptoms in children

• The colour tends to fade slowly as the child grows, often becoming less visible each year
• Most patches have faded a lot by age 3 to 5, and many are gone by school age
• Some children keep a faint patch into their teenage years
• A fading patch may look slightly greenish or brownish before it disappears
• Your child grows and develops normally — the mark does not affect movement, feeling or health

Symptoms in older adults

• In most people the patch has faded completely long before adulthood
• In a small number of people a faint patch remains, usually on the lower back or buttocks
• A patch that remains is unchanged and harmless, and needs no treatment
• It does not turn into skin cancer and does not need to be watched like a mole

Causes

Main causes

• Pigment-making cells (melanocytes) settle deeper in the skin than usual while a baby is developing in the womb
• Because the pigment sits deep, light reflects back through the skin and looks blue-grey, in the same way a vein looks blue through the skin
• It is not caused by trauma, bruising, an infection, or anything the parent did during pregnancy
• It runs in families to some extent, but there is no single 'gene' for it

Risk factors

• Having darker skin, or belonging to a group where the birthmark is very common
• Family history of similar birthmarks
• Being born with a very extensive patch covering a large part of the body — this is uncommon and is usually checked to rule out other conditions

When to see a doctor

See a doctor urgently if:

• A patch that becomes raised, warm, painful, blistered or starts to bleed
• Lots of new bruise-like marks appearing along with other injuries or concerning symptoms
• Widespread or very numerous patches plus poor feeding, slow growth, or delayed development — see a doctor promptly
• Any baby who seems unwell in themselves

Book a routine appointment if:

• You want the mark checked and written down in your baby's health record
• You are worried it might be mistaken for a bruise by a caregiver, teacher or health professional
• The mark is still clearly visible in an older child and you would like advice
• A patch is in a very visible place and you have questions about how it will fade

Diagnosis

In most cases a doctor, midwife, health visitor or nurse can tell what it is just by looking. The flat shape, blue-grey colour, typical position on the bottom or lower back, and the fact that it was there from birth are usually enough. No tests are needed for a typical patch.

Tests that may be done

• Usually none — a physical examination is enough
• A dermatoscope (a small magnifying light used by skin doctors) may be used if the diagnosis is unclear
• A skin biopsy (a tiny sample of skin) is only very occasionally needed if the mark looks unusual
• Blood or urine tests may be suggested in the rare case of very widespread patches together with other symptoms, to check for an underlying condition
• Photographs and a written note in the baby's health record, so the mark is documented

What to expect at your appointment

The appointment is quick and gentle — the doctor will simply look at the skin. You may be asked when the mark first appeared and whether anyone else in the family has one. Ask for the mark to be written in your baby's red book or health record, so there is a note of it from the start. This protects you and your child if the mark is ever seen by someone new.

Treatment

No treatment is needed. Congenital dermal melanocytosis fades by itself over months to years and does not cause harm. The main 'care' is making sure the mark is recognised for what it is and written in your child's records.

Self-care at home

• Keep the skin clean and use a gentle, unperfumed moisturiser if the skin is dry — this is for general skin care, not to treat the birthmark
• Take a dated photo and note it in your baby's health record so there is a clear record of the mark from early on
• Tell anyone who cares for your child — grandparents, childminders, nursery staff, sports coaches — that the mark is a birthmark and not a bruise
• Use sunscreen on any birthmark on skin that is exposed to the sun, as you would for the rest of your child's skin
• Give your child the usual childhood vaccinations and health checks — they are not affected by the birthmark

Medical treatments

There is no medicine, cream or other treatment that is needed for this birthmark, and none is recommended. Treatments sometimes advertised online for 'removing birthmarks' are not appropriate here and can harm a child's skin. If the look of a patch is causing a lot of distress, talk to a skin doctor (dermatologist) about the options rather than trying anything at home. Any decision about treatment would only ever be made together with your child's own doctor.

When is surgery considered?

Surgery is not used for congenital dermal melanocytosis. Because the birthmark fades on its own and sits in the deeper layer of skin, cutting it out or lasering it is not appropriate.

Living with this condition

Life carries on exactly as normal. Your child can be bathed, massaged, cuddled, vaccinated and take part in sports just like any other child. The most useful thing you can do is make sure the mark is documented and that everyone who cares for your child knows about it.

Lifestyle tips

• Note the birthmark in your baby's health record and keep a dated photo
• Tell nursery, school and anyone who looks after your child that it is a birthmark
• Use sun protection on any exposed skin, as for any child
• Expect the patch to slowly fade — check with your own doctor at routine visits if you want reassurance
• If your child is old enough to notice it, talk about it simply and calmly as part of who they are

Diet and exercise

No special diet or exercise is needed. Ordinary healthy eating and plenty of play and movement are all your child needs. The birthmark does not affect how active your child can be.

Mental health and emotional wellbeing

Many parents worry, especially if someone has ever asked whether the mark is a bruise. That worry is understandable and very common. It can help to talk it through with your health visitor, midwife or doctor, who can reassure you and write the birthmark in the notes. If you feel anxious or low about your child's health, or about being questioned, you deserve support — speak to your doctor, who can point you to the right service. As your child grows, talk about the mark in a matter-of-fact, positive way, so it never feels like a secret or something to be ashamed of.

Prevention

No — this birthmark cannot be prevented, and nothing during pregnancy causes it. It forms while the baby is developing in the womb. Parents should not feel any blame.

Vaccines

There is no vaccine for this birthmark. Your child should still have all the usual childhood vaccinations on the normal schedule — the birthmark makes no difference.

Screening programmes

No screening is needed for a typical birthmark. It is simply checked by looking at routine baby checks. If a baby has very many or very widespread patches, a doctor may suggest a check for other conditions — this is uncommon.

Complications

If left untreated

• Usually none — the birthmark fades by itself and causes no health problems
• The main risk is being mistaken for a bruise, which can cause worry or, rarely, lead to unfair concerns about how a child is being cared for
• Some children may feel self-conscious if a patch is in a visible place and still there when they are older
• Very rarely, widespread patches are linked with a metabolic (body chemistry) condition — this only applies when there are many patches plus other signs such as developmental delay or feeding problems

Long-term outlook

The outlook is excellent. Congenital dermal melanocytosis is harmless, does not turn into skin cancer, and fades over time in most children. Your child can live a completely normal, active, healthy life. If you ever feel unsure, your own doctor is there to help.

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