Mastocytosis
Introduction
Mastocytosis (mas-toh-sahy-toh-sis) is a condition where there is an abnormally high number of mast cells present in different body parts such as the skin, bone and blood, causing a vareity of symptoms. It can be divided into disease that affects the skin alone or the whole body. In children mastocytosis is almost always just skin related without involving other body parts. Therefore, for the purpose of this article, we will only discuss mastocytosis that affects the skin.
Mast cells are a type of immune cell that are involved in allergic reactions. When they are triggered, mast cells release chemicals within the skin that can cause swelling, redness and itch in the affected part of the skin.
Children with skin mastocytosis have an abnormally high number of mast cells in their skin, but not elsewhere in the body. There are three main types of skin mastocytosis:
Solitary mastocytoma
Urticaria pigmentosa
Diffuse cutaneous mastocytosis
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A small solitary mastocytoma on the leg of a baby
Who gets it?
Mastocytosis is rare. However, there are no exact figures to estimate exactly how rare it is. Childhood mastocytosis can occur any time between birth to late teens but most commonly appears within the first 6-12 months of life. It tends to affect boys more than girls.
What causes it?
In most children there is no obvious cause. In some cases, mastocytosis may be caused by a genetic abnormality in the child which can cause the body to produce too many mast cells. However, most cases of mastocytosis are not passed down from parents to their children, and it is rare for mastocytosis to affect more than one family member.
It is not an infection and therefore not contagious.
What does it look and feel like?
Looks like…
Urticaria pigmentosa: red or brown patches on the face, chest, back, arms and legs that look like moles and continue to pop up throughout childhood
Solitary mastocytomas: a single thickened or flat area of reddish to brown skin which presents soon after birth and tends to disappear around adolescence
Diffuse cutaneous mastocytosis: thickened and leathery skin affecting a large area, with occasional blistering
Feels like…
Your child can become itchy particularly with the diffuse cutaneous mastocytosis.
Rubbing or scratching the affected area may cause more redness, swelling, itching and sometimes blistering. Blistering is more common in diffuse cutaneous mastocytosis.
If there are only one or two spots, the chemicals released by the mast cells are not enough to cause any problems. Your child will remain healthy and well.
If there are many spots on the skin, sometimes your child may have symptoms include flushing, irregular heart beat, tiredness, headache, diarrhoea, vomiting and tummy pain.
Very rarely, more severe reactions like fainting, breathing difficulty and wheezing may occur.
What tests might be needed?
A dermatologist can diagnose your child with mastocytosis by looking at their skin and asking a few questions about it. They may rub the skin over the rash making it become raised and red, which is a sign to support the diagnosis. They may also want a small sample of your child’s skin, called a skin biopsy, to confirm the diagnosis.
If there is any indication your child may have mastocytosis affecting more than just the skin (systemic mastocytosis), then further tests will be necessary which can be arranged by a paediatrician.
What treatments are available?
What can I do?
The most helpful thing that you can do is to help your child avoid any triggers that can make their skin worse. Some common triggers include
extreme and sudden change of temperatures eg hot baths, cold swimming pools, drinking hot drinks
exercise
lack of sleep
irritability or stress
fever
skin rubbing
certain medications - some medications should be avoided. Most of these are not normally given to children. Medications to be avoided inlude aspirin, other nonsteroidal anti-inflammatory drugs such as children's ibuprofen, codeine in cough medications, radiocontrast agents for imaging studies, muscle relaxants if your child were to undergo surgery with anaesthesia, local anaesthetic if your child were to have skin surgery, etc
Children with some types of skin mastocytosis can have a severe allergic reaction or anaphylaxis to bee or wasp stings, thus they may need to carry an Epipen.
Medical therapies
Most forms of skin mastocytosis are not serious and do not require any treatment. If they cause symptoms then treatments can be used to reduce itch and discomfort:
Steroid creams can reduce your child's itch and prevent their skin from blistering.
Allergy medications (antihistamines) taken by mouth can reduce the itch.
Phototherapy is reserved for children who have a large part of their skin affected.
Adrenaline/epinephrine (EpiPen) should be used if your child has an anaphylactic reaction.
Surgery may be considered for solitary mastocytomas. However, this is usually not necessary.
What happens after treatment?
Treatment is aimed at making symptoms such as itch and abdominal pain better. In children with skin mastocytosis only, it will most likely go away by itself, but this may take many years. About 8 in 10 children who have mastocytosis no longer have symptoms by the time they are teenagers. A very small number of children with mastocytosis will continue to have symptoms into adulthood, and the disease can go on to affect other parts of the body.
Regular follow up with your child's dermatologist is recommended long-term.
What support is available?
Your GP and your dermatologist will be able to answer any questions you may have about your child’s skin, and they will also be able to advise you on how to manage their skin.
The Australian Mastocytosis Society (TAMS) offers support groups for people who have mastocytosis, and they are currently developing a program for parents and children (TAMS kids) - http://mastocytosis.org.au
Authors/Reviewers:
Author: Dr Samantha Ting
Paediatric Reviewer: Dr Mayuri Sivagnanam
Photos courtesy of Dr Deshan Sebaratnam
Editor in Chief: Dr Tevi Wain
