What is Urticaria Pigmentosa ?
Mastocytosis is a condition that results in the buildup of mast cells, often in areas like your skin, bone marrow, liver, and various digestive and lymphatic tissues. The World Health Organization (WHO) has categorized a form of mastocytosis affecting the skin, known as cutaneous mastocytosis, into three main types.
The first type has one or just a few (three or less) spots or lesions called “mastocytomas.” The second type, called urticaria pigmentosa (UP), has multiple spots ranging from more than ten to less than a hundred. The final type involves widespread involvement of the skin.
UP is the most common type of skin mastocytosis in children, but it can also occur in adults. It’s usually a mild condition that often gets better on its own, especially during the teenage years. Unlike other forms of mastocytosis, internal organs are rarely affected in UP.
What makes UP unique are the small, itchy reddish-brown or yellowish-brown spots or patches on the skin, often described as “urticaria” or hives. These usually appear during childhood and can last all throughout a person’s life. The severity of UP can differ from person to person. While often harmless, it could sometimes cause symptoms and complications linked to increased activity of mast cells. It is vital for medical professionals to understand the characteristics, causes, and ways to manage UP.
What Causes Urticaria Pigmentosa ?
Urticaria pigmentosa (UP), also known as mastocytosis, is caused by changes, known as mutations, in a gene named KIT. These changes can make mast cells, a type of cell that is part of our body’s immune system, act abnormally when they come across certain triggers. These triggers can be certain foods, exercise, heat, insect stings, skin injuries, alcohol, painkillers, anti-inflammatory drugs, certain antibiotics like polymyxin B, and medications used to control body functions like heart rate and digestion.
When triggered, these mast cells release substances such as histamine, eicosanoids, prostaglandins, leukotrienes, heparin, proteases, and cytokines. All these substances, which are usually used by our body to protect itself, can end up causing the symptoms of mastocytosis when released in large amounts. These symptoms can include itchy and red skin lesions, a sudden drop in blood pressure, stomach upset, breathing difficulties and even anaphylaxis, a severe and sudden allergic reaction that needs immediate medical treatment. Some anesthesia drugs can also trigger anaphylaxis in some individuals.
Risk Factors and Frequency for Urticaria Pigmentosa
Mastocytosis is a condition that can occur right from birth or develop at any age, even into late adulthood. It affects people of all races equally and doesn’t favor a particular gender. Despite the majority of patients lacking a family history of mastocytosis, there have been instances of this condition occurring within families.
- In 15% to 50% of patients, cutaneous mastocytomas, a type of skin lesion, occur.
- Urticaria pigmentosa (UP), another skin symptom, is seen in 45% to 75% of patients.
- Less than 5% to 10% of patients experience wide-ranging skin involvement.
Interestingly, this condition is most often reported in individuals with white skin, as skin lesions associated with mastocytosis are less visible in those with darker skin. Also, a significant discovery has been made that instances of autism spectrum disorders in children with mastocytosis are ten times higher than in the general population.
Signs and Symptoms of Urticaria Pigmentosa
Urticaria Pigmentosa (UP) is a skin condition that’s noticeable by small, even-sized spots that are tan to brown in color. These spots are usually found on the trunk of the body and don’t typically appear on the central face, palms, or soles of the feet. The spots can vary in number and are generally between 1 to 2 cm in size, although some might be bigger. A symptom called Darier’s sign can happen when someone with UP rubs or strokes a spot, causing a welt to form. This happens because of a release of substances from cells in the skin, which can lead to whole-body symptoms. Some spots may even turn into blisters after they’re rubbed or stroked. Darier’s sign is often more noticeable in children because they have a higher concentration of these cells in their spots.
About half the people with UP may also get a skin response called dermographia when uninvolved skin is stroked. Other forms of UP can form larger, blood-filled blisters or small, infiltrating water blisters. Blisters are more common in infants, and as the person ages, the skin may develop a grainy-leather look, or the skin might appear pseudoxanthomatous, which means yellow, thick, and lumpy.
Some people with UP may also experience widespread symptoms, including:
- Itching (pruritus)
- Abdominal pain
- Red facial flushing
- Diarrhea
- Dizziness
- Heart palpitations
- Fainting (syncope)
About a quarter of people with UP may also have gastrointestinal issues. If people with UP complain of fever, malaise, night sweats, severe gut pain, weight loss, or cognitive problems, this may indicate the presence of disease outside the skin. The extensive release of substances from cells in the skin can even result in fatal shock.
Testing for Urticaria Pigmentosa
If you’re experiencing GI symptoms, like stomach pain or discomfort, your doctor might request a barium study or endoscopy. A barium study involves drinking a liquid that helps improve the visibility of your digestive tract in an X-ray. An endoscopy involves using a flexible, tube-like camera to look at your digestive tract. Similarly, if you’re feeling bone pain or have had fractures, your doctor may ask for a skeletal survey or a bone scan.
During your physical examination, doctors are specifically checking for lymphadenopathy (swollen glands) and hepatosplenomegaly (enlarged liver or spleen). If they suspect any issues with your liver or spleen, an ultrasound or CT scan of the liver might be recommended. Ultrasound uses sound waves to create images of these organs, while a CT (computed tomography) scan takes detailed pictures of your body from different angles.
If any of these tests turn up something unusual, your doctor may consider a bone marrow biopsy. This procedure involves taking a small sample of your bone marrow to examine it more closely. A complete blood count (CBC), which checks the different types of cells in your blood, a serum tryptase level, which measures a certain enzyme in the presence of an allergic reaction, liver function tests, and a KIT gene analysis may also be recommended. Note that some consider these tests as optional in children.
Tryptase levels can be more informative than histamine levels, as histamine can be increased in conditions causing high eosinophils (a specific type of white blood cells) count.
Your physician may remember the criteria for diagnosing systemic mastocytosis, a condition where too many mast cells (a type of immune cell) are produced, in case of your symptoms progress. The World Health Organization (WHO) guidelines for diagnosing systemic mastocytosis involves certain major and minor criteria. Major factors involve having dense cell groups in bone marrow or tissues outside of the skin. Minor factors can include observations of abnormal mast cells, certain indicators called CD25 or CD2 on mast cells, a particular mutation in the KIT gene, or a specific level of serum tryptase.
In case of cutaneous mastocytosis, a condition that primarily affects skin, the diagnosis is less defined. Often, it’s diagnosed by a visual check of skin lesions, especially in children. This too involves certain criteria. The typical skin lesions are a major pointer. Additionally, microscopic examination of cell groups and the presence of a specific mutation in the KIT gene in the affected skin act as minor indicators.
Treatment Options for Urticaria Pigmentosa
Managing skin conditions like cutaneous mastocytosis (a disease caused by an excess of certain types of cells in the skin) starts with simple things like bathing with lukewarm water, using air conditioning during hot weather, and staying away from anything that could trigger the release of more of these types of cells. The treatment given depends on the symptoms of each person with cutaneous mastocytosis.
Topical medications (creams or gels) that can be applied directly to the skin include drugs that reduce the activity of the immune system (calcineurin inhibitors) and corticosteroids (drugs that reduce inflammation). Sometimes, a strong topical corticosteroid may be required and covered with a dressing to enhance its effects (occlusion). Injecting small amounts of diluted corticosteroids directly into the skin lesions could help resolve them either temporarily or long-term. By only treating specific areas of the body at a time, doctors aim to reduce the risk of things like skin thinning (‘skin atrophy’) and over-suppression of the adrenal gland, which naturally produces corticosteroids.
Systemic corticosteroids can be taken orally and impact the entire body and are only useful in certain situations like severe skin disease, excess fluid in the abdomen (‘ascites’), and poor absorption of nutrients in the gut (‘malabsorption’). Although there are instances where these drugs have led to full disease recovery, they are often unimpressive due to the fact that their main action is to move mast cells around rather than getting rid of them.
Systemic treatments like oral antihistamines (which are most often used), medicines to treat gastrointestinal symptoms (oral cromolyn sodium), and various others, including treatments which use ultraviolet (UV) light can be used. It’s also important for patients to have access to an epi-pen to inject themselves with adrenaline during severe allergic reactions.
To manage cutaneous mastocytosis, patients should avoid physical stressors such as emotional stress, extreme temperatures, and physical strain. Also, they should avoid certain foods and medications that could trigger a reaction, like aspirin, certain narcotics, alcohol, and even certain seafood, spicy foods or hot beverages. Though it’s currently theoretical, avoiding these things is generally recommended until further research can confirm their role. There’s also one case where a gene mutation related to cutaneous mastocytosis was successfully treated with the medication imatinib, which appeared to stop disease symptoms, prevent disease progression, and lengthen the overall course of the disease.
What else can Urticaria Pigmentosa be?
When physicians are diagnosing skin conditions, they may consider various diseases that show similar symptoms. These could include:
- Bullous impetigo (a contagious skin infection causing blisters)
- Secondary syphilis (a sexually transmitted infection)
- Carcinoid (a slow-growing type of neuroendocrine tumor)
- Leiomyoma (benign muscle tumors)
- Urticaria (also known as hives)
- Juvenile xanthogranuloma (a benign skin condition commonly seen in children)
- Reactions to insect bites and stings
- Auto-immune bullous diseases (a group of diseases causing blistering)
Moreover, increased numbers of mast cells, a type of white blood cell, can not only be seen in these conditions but also in other skin conditions like dermatofibromas (benign skin growths), psoriasis (skin disease causing red, itchy patches), atopic dermatitis (a type of eczema), and nevi (moles). Nevertheless, all these disorders come with unique changes in the skin, which helps physicians differentiate one from the other.
What to expect with Urticaria Pigmentosa
The outlook for children suffering from mastocytosis, a condition in which there are too many mast cells – a type of immune cells – in the body, is generally very favorable. About 50% to 70% of children with mastocytosis tend to recover before they hit their teenage years.
However, if mastocytosis starts showing symptoms after a child turns 10, the illness might become more difficult to treat. Late-onset disease often sticks around longer and is more likely to evolve into a systemic disease, which means it affects the entire body. It also carries a higher risk of turning into cancer.
Possible Complications When Diagnosed with Urticaria Pigmentosa
The potential complications of mast cell leukemia can be quite serious. One of these complications is the possible evolution into a blood cancer known as mast cell leukemia. Another serious complication or risk factor is the death that might result from the rapid release of too many mast cells (a condition called mast cell degranulation).
Complication risks:
- Possible progression into a form of blood cancer (mast cell leukemia)
- Death due to a large number of mast cells releasing their contents rapidly (mast cell degranulation)
Preventing Urticaria Pigmentosa
Teaching patients about things that may make their condition worse, like certain foods, medications, bug bites, or physical conditions, is a part of preventing problems. When patients understand and avoid these triggers, they can lessen their symptoms and improve their overall well-being. At the same time, it’s important for patients to understand what UP is – it usually doesn’t cause major problems and it rarely affects internal organs.
Patients also need to learn about how crucial it is to manage their medications correctly, make necessary lifestyle changes, and keep regular appointments with their doctor. It’s important to emphasize that catching problems early and getting regular medical check-ups can prevent further issues related to mast cell activation – this term refers to an immune response that can lead to various symptoms.
Patients need to know how to recognize signs that the condition may be affecting their entire body, and when to seek medical help immediately. By combining strategies to prevent problems and providing thorough patient education, healthcare professionals can help people with UP play an active role in managing their condition effectively, which can greatly improve their quality of life.