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Mastocytosis causes a wide range of symptoms, which can vary depending on the type of mastocytosis you have.

Skin lesions are a characteristic of cutaneous mastocytosis. Types of lesions known to occur in cutaneous mastocytosis include:

  • small areas of skin that change colour (macules)
  • small firm, raised bumps (papules)
  • larger raised, red bumps (nodules)
  • large raised areas of skin noticeable to the touch (plaques)
  • blisters – which mainly affect young children with mastocytomas (tumours consisting of mast cells) or diffuse cutaneous mastocytosis (a rare form of cutaneous mastocytosis)

Lesions usually develop on the trunk rather than the head, neck and limbs.

The lesions, known as urticaria pigmentosa, are usually yellow-tan to reddish-brown in colour, and can range from 1mm to several centimetres in size.

The number of lesions that develop on the skin can vary widely. For example, it's possible for only a single lesion to develop, or more than 1,000.

Stroking the affected areas of skin can make it swollen, itchy and red over the lesion.

If you have systemic mastocytosis, you may develop sudden episodes of symptoms that last for around 15-30 minutes. However, many people do not have any problems.

The most common symptoms experienced during an episode are:

  • hot flushing – described as a dry feeling of heat, rather than the sort of wet heat you experience when sweating
  • a forceful or rapid heartbeat (heart palpitations)
  • lightheadedness

Less common symptoms during an episode include:

  • headache
  • shortness of breath
  • chest pain
  • feeling sick
  • diarrhoea

Once the episode has passed you'll probably feel sluggish for several hours.

The episodes are caused by the mast cells suddenly releasing excessive amounts of histamine, usually after you're exposed to certain triggers.

Triggers known to cause episodes include:

Abnormal mast cells in your bone marrow and organs can also cause related symptoms, including:

  • stomach pain caused by peptic ulcers
  • loss of appetite
  • joint pain
  • weakness
  • fatigue
  • changes in mental state – such as confusion, irritability, poor attention span and impaired memory
  • urinary symptoms – such as needing to pee frequently or pain when peeing

In more severe cases of mastocytosis, the following symptoms may occur:

  • weight loss
  • swelling of the lymph nodes
  • swelling of the liver – which can cause jaundice and make you feel lethargic
  • swelling of the spleen – which can cause tummy and shoulder pain

Some people with severe symptoms experience a sudden fall in blood pressure during an attack. 

Low blood pressure (hypotension) can trigger a number of associated symptoms, such as:

  • dizziness
  • fainting
  • blurred vision
  • confusion
  • general weakness

If you have systemic mastocytosis or extensive cutaneous mastocytosis, your risk of a severe allergic reaction (anaphylaxis) is increased.

It's important to look out for the initial symptoms of anaphylaxis, which include:

  • itchy skin or a raised, red skin rash
  • swollen eyes, lips, hands and feet
  • feeling lightheaded or faint
  • narrowing of the airways, which can cause wheezing and breathing difficulties
  • abdominal pain
  • feeling and being sick

Dial 999 immediately and ask for an ambulance if you think you or someone else is experiencing symptoms of anaphylaxis.