Key takeaways
- Hives are a common skin condition. Most cases are acute, meaning they resolve relatively quickly.
- Chronic hives last longer than 6 weeks and can be divided into two categories: chronic inducible urticaria (CIndU) and chronic spontaneous urticaria (CSU), which lacks a clear cause.
- Diagnosing hives involves a physical examination, a review of symptoms, and potentially allergy testing to identify triggers.
Knowing the type of hives a person has can help them manage and reduce symptoms, which in turn can improve their quality of life.
Read on to learn more about the types of hives, their unique characteristics, and when to contact a doctor.
Around 20% of people experience hives at some point in their lifetime, and in most cases, they are acute, meaning they get better quickly.
If a person knows what caused the hives and can avoid it, the symptoms may improve within a few days. Often, they are the result of an allergic reaction to a substance, such as:
- plants such as nettles
- skin irritants such as fragrance
- metals such as cobalt or nickel
- foods such as seafood or eggs
Hives can also be a response to an infection. Sometimes, acute hives have no clear cause.
However, some people find that their hives last a longer period of time. Although each individual hive typically disappears within 24 hours, they can continue to come and go over days, weeks, or longer.
If hives persist for more than 6 weeks, this is known as chronic hives. Within this category, several subtypes exist.
Chronic inducible urticaria (CIndU) is a form of chronic hives in which there is a clear, identifiable cause. This is what makes them “inducible”, as contact with the trigger will cause symptoms. “Urticaria” is the medical name for hives.
The triggers for CIndU can include:
- pressure (dermatographia)
- vibration (vibratory urticaria)
- sunlight (solar urticaria)
- raised body temperature (cholinergic urticaria)
- water (aquagenic urticaria)
- hot temperatures
- cold temperatures
CIndU can also occur due to contact with a specific substance. However, the hives themselves must be persistent for at least 6 weeks to be considered chronic.
These specific forms of CIndU vary in terms of how severe and how rare they are. The table below summarizes key information about them:
| Type | Trigger | Prevalence | Severity |
|---|---|---|---|
| Dermographism | Scratching the skin | The most common form of CIndU. It affects 2% to 5% of all people. | Usually not severe |
| Pressure urticaria | Physical pressure | Uncommon | Can be more severe and require higher doses of antihistamines |
| Cold urticaria | Cold temperatures | Uncommon | Can be severe and cause anaphylaxis |
| Heat urticaria | Direct contact with heat | Rare | Can range from mild to severe, but 60% of people respond well to antihistamines |
| Solar urticaria | Skin exposure to the sun | Rare | Can range from mild to severe. May vary depending on the level of sun exposure. |
| Vibratory urticaria | Contact with vibrating objects | Rare | Usually only affects the skin, but it can be severe if a person has exposure to vibrating equipment for long periods |
| Cholinergic urticaria | Increased body temperature from exercise, sweating, stress, or eating spicy food | Common | Usually only affects the skin, but it can cause anaphylaxis in some people |
| Aquagenic urticaria | Contact with water | Very rare | Usually only affects the skin and is rarely life threatening |
CIndU is more common among younger people.
Unlike CIndU, which has a clear cause, chronic spontaneous urticaria occurs without an identifiable cause.
According to the nonprofit Allergy UK, CSU has an association with autoimmune conditions. These are conditions in which the body’s immune system attacks healthy tissues.
The
- autoimmune hypothyroidism
- rheumatoid arthritis
- systemic lupus
- Sjogren syndrome
- celiac disease
- type 1 diabetes
CSU can also develop after an infection, but scientists have not yet proven a causal link between the two.
CSU tends to affect adults between 20 and 40 years, although it can also affect children. In 80% of cases, the hives resolve on their own in between 1 to 2 years, but in some people, they last much longer.
While children can experience any of the above types of hives, their symptoms may differ from those of adults.
According to DermNet, around 40% of children with hives also have angioedema, which is a type of swelling under the skin.
It is also much more likely for hives in children to be acute rather than chronic. Children are more likely to have hives due to an allergy or infection than other causes, particularly viral infections.
To diagnose hives, a doctor may begin by performing a physical examination of the skin.
To determine which type of hives a person has, they may:
- ask about a person’s symptoms, such as when they occur and for how long
- take a medical history, including information about any allergies or medications
- ask the person to keep a symptom diary to determine if there may be a specific trigger
- refer them for allergy testing
If an allergist can find a specific trigger, the person may have contact hives. Through investigation, medical professionals or patients may also be able to identify other types of triggers, such as pressure, vibrations, hot or cold temperatures, or water exposure.
If there are no clear triggers and the symptoms last a long time, a doctor may diagnose CSU. They may also test for signs of autoimmune conditions that may have a connection with the hives.
A person should speak with a doctor if they have hives that do not improve on their own or keep recurring. A person may need help identifying the cause and managing the symptoms.
Contact a doctor promptly if hives:
Seek immediate help if a person has any potential signs of a severe allergic reaction.
Anaphylaxis: Symptoms and what to do
Anaphylaxis is a severe allergic reaction that can be life threatening. The symptoms develop suddenly and include:
- hives
- swelling of the face or mouth
- wheezing
- fast, shallow breathing
- a fast heart rate
- clammy skin
- anxiety or confusion
- dizziness
- vomiting
- blue or white lips
- fainting or loss of consciousness
If someone has these symptoms:
- Check whether they are carrying an epinephrine pen. If they are, follow the instructions on the side of the pen to use it.
- Dial 911 or the number of the nearest emergency department.
- Assist the person in moving from a sitting position to lying down. If they have vomited, turn them onto their side.
- Stay with them until the emergency services arrive.
Some people may need more than one epinephrine injection. If the symptoms do not improve in 5 to 15 minutes, or they come back, use a second pen if the person has one.
Hives can be acute or chronic. Within these categories, there are many subtypes of hives. However, most cases are short-term and get better on their own in several days.
Less common types of hives include pressure urticaria, cold urticaria, and solar urticaria. Some people have chronic hives with no identifiable cause, which is known as CSU. Some people with CSU may have autoimmune conditions.
Anyone who is worried about hives that do not improve or keep coming back should speak with a doctor.