Diagnosing chronic hives is not always easy. This is because many other conditions cause hives. Also, the cause of chronic hives is usually unknown. Your doctor needs to rule out any other causes of your symptoms to help you manage and treat your hives.
Many people with chronic hives experience a delay in diagnosis. During this time, doctors will use your health history and lab tests to determine a diagnosis. They may also refer you to specialists to help rule out other conditions. Usually, doctors use 3 things to diagnose chronic hives:1-4
- Your health history
- A physical exam
- Identifying triggers that worsen or cause symptoms
Physical exam and health history
A detailed history of your symptoms is the most important part of diagnosis. It may be helpful to use a diary to keep track of your symptoms, activities, and any triggers. Your doctor will ask about:1,2
- Shape, size, and site of hives
- Frequency, timing, and duration of hives
- Whether you also have swelling under skin (angioedema)
- Family history of hives and swelling
If your symptoms are consistent with chronic hives, doctors will ask questions to identify possible causes. The goal is to make sure you do not have a more serious condition, such as an autoimmune disorder.2,3
Usually, your doctor can distinguish chronic hives from similar conditions based on a detailed description of your symptoms. They may ask you about:2,3
- New drugs you are taking, including antibiotics and anti-inflammatory drugs
- Recent travel
- Infections
- Changes in health status
- Sexual history
- Response to previous therapies
- Physical or emotional triggers of symptoms
- Other symptoms, such as fever, weight loss, joint pain, or stomach pain
- Family history of hives or autoimmune disease
Once doctors rule out these causes, there is a high chance you have chronic idiopathic hives. This means that no cause can be identified.2
There is no single test that gives your doctor a definite answer about whether or not you have chronic hives. Doctors may perform a number of tests to rule out other conditions. Usually, these tests will not reveal problems if your health history does not indicate other conditions.
Some of the tests your doctor may perform include:2,4
- Blood tests such as complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level
- Skin tests, such as a biopsy of newly formed hives
- Challenge/provocation tests if a physical cause is suspected
Once the results come back, your doctor uses them, along with your health history and physical exam, to make a diagnosis.
Why does it take so long to diagnose chronic hives?
The time from when symptoms begin to diagnosis varies for each person. Diagnosis can take as short as a couple of weeks or as long as several years. A proper diagnosis may be delayed because of several factors, including:5
- Lack of awareness about chronic hives
- Uncertainty about conditions with no known cause
- Symptoms that come and go
- Time spent ruling out other conditions
Many conditions are easy to confuse with chronic hives. The 2 most similar conditions are urticarial vasculitis (blood vessel inflammation) and mastocytosis (too many mast cells in the body). However, your doctor and specialists can rule out these conditions based on descriptions of your hives.1
When do I need to see a specialist?
Your primary care doctor may be able to diagnose hives themself. But in some cases, they may need to refer you to a specialist. Some situations when you may need to see a specialist include:6
- When they suspect an underlying disorder
- If you have signs or symptoms of urticarial vasculitis
In these situations, you may have to see a dermatologist or an allergist/immunologist. These are doctors who can perform more detailed tests for skin and allergic conditions. For example, an allergist may use skin and blood tests to identify any allergens.7,8