Condition: Anaphylaxis in mastocytosis

Mastocytosis is a rare disease of the skin in where mast cells gather in body tissues, such as the skin, internal organs and bones. When mast cells detect a substance that triggers an allergic reaction (an allergen), they release histamine and other chemicals into the bloodstream which can cause mild to life threatening reactions.

The causes of mastocytosis are not fully known, however it is believed that there is a correlation with a change in genes known as the KIT mutation, which makes the mast cells more sensitive to the effects of a protein called stem cell factor. Abnormally high number of mast cells in an individual with mastocytosis create the potential to release large amounts of histamine into the blood.

Symptoms of mastocytosis include skin blisters, nausea, stomach pain, diarrhea, vomiting, brown or red blotches on the skin, bumps or spots that itch, flushing, and fainting. The symptoms of anaphylaxis include nausea and vomiting, weak and rapid pulse, and skin rashes.

The following tests are commonly used to look for signs of mastocytosis:

• Skin tests – Your GP or skin specialist (dermatologist) may rub the affected areas of skin to see if it becomes red, inflamed and itchy. This is known as Darier’s sign.
• Blood tests – including a full blood count (FBC) and measuring blood tryptase levels
• Ultrasound – an ultrasound scan to look for enlargement of the liver and spleen if it seems likely a DEXA scan to measure bone density
• A bone marrow biopsy test – where a local anaesthetic is used and a long needle is inserted through the skin into the bone underneath, usually in the pelvis

There’s no proven cure for mastocytosis, so it is advised to stay away from the things that trigger your symptoms. Other treatments used to try to relieve the symptoms include:

• Antihistamines – used to treat the symptoms of red skin and itchiness
• Steroid cream – used to treat mild to moderate cases of cutaneous mastocytosis