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 and limbs rather than the head and neck.

The lesions, known as urticaria pigmentosa, are usually 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.

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

If you have systemic mastocytosis, you may experience episodes of symptoms. However, many people do not have any problems.

The most common symptoms experienced during an episode are:

• hot flushes
• a forceful or rapid heartbeat (heart palpitations)
• feeling lighthead

Less common symptoms during an episode include:

• headache
• chest pain
• feeling sick
• diarrhoea

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:

• physical factors – such as heat, overheating, cold, fatigue and physical exertion
• emotional factors – such as stress and excitement
• insect bites or stings
• infection – such as a cold or flu
• alcohol
• certain medications – such as ibuprofen, aspirin and antibiotics
• certain foods – such as cheese, shellfish and spices

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

• stomach pain caused by peptic ulcers
• joint pain
• weakness
• fatigue
• changes in mental state – such as confusion, irritability, poor attention span and impaired memory

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
• generally feeling weak

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 rash
• swollen eyes, lips, hands and feet
• feeling lightheaded or faint
• narrowing of the airways, which can cause wheezing and breathing difficulties
• stomach 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.