Hives (Urticaria) – Assessment by a Dermatologist
A specialist in dermatology assesses chronic and recurrent hives in children and adults and develops a treatment plan.
Hives (urticaria) is an itchy rash with raised red or pale wheals that appear and disappear within hours, often together with deeper swelling of the skin (angioedema). If the hives last for more than 6 weeks, the condition is referred to as chronic urticaria. At Charlottenlund Privathospital, hives are assessed by Susanne Birkballe, specialist in dermatology, through a consultation, examination and, when needed, blood tests and skin prick testing. Based on the findings, a plan is made for treatment and follow-up. Both children and adults can be examined.
What are hives?
Hives occur when cells in the skin release histamine and other chemical messengers, causing small blood vessels to leak fluid into the skin. This creates wheals—raised, itchy patches that look like the marks left by stinging nettles. Each wheal usually disappears within a day, while new ones may appear elsewhere. In some people, deeper layers of the skin also swell, usually around the eyes, lips, hands or feet. This is called angioedema.
Doctors distinguish between acute and chronic hives. The dividing line is 6 weeks.
Acute hives
- Lasts less than 6 weeks, often just a few days
- Often triggered by an infection, especially in children
- Can be caused by medications, foods or insect bites
- Usually clears up on its own
Chronic hives
- Lasts more than 6 weeks
- Comes and goes over months or years
- Often has no external cause (spontaneous)
- Can be triggered by cold, pressure, heat or exercise
Acute hives are very common. According to the international guideline on hives, around 20% of people experience acute hives at some point in their lives. Chronic hives are less common: a pooled analysis of population studies found that around 0.5% of people in Europe had chronic hives at any given time.
Source: Zuberbier et al., international guideline for urticaria, Allergy 2022
What triggers hives?
Acute urticaria is most often triggered by a viral infection, particularly in children. Other triggers include certain types of medication, foods and insect stings.
With chronic urticaria, an external cause is usually not found. The rash occurs spontaneously because the immune system itself activates cells in the skin, and it is rarely caused by allergy. In some people, the rash is triggered by physical factors such as cold, pressure on the skin, heat, sunlight or scratching, or by sweating during physical activity. In the most common physical form, lines of wheals develop where the skin has been scratched or rubbed. Stress and infections can worsen chronic urticaria.
Hives are not contagious.
When should you seek medical attention for hives?
Call 112 if hives are accompanied by difficulty breathing, difficulty swallowing, swelling of the tongue or throat, or dizziness. These may be signs of a severe allergic reaction.
You should see a dermatologist if the hives have lasted for more than 6 weeks, keep returning, are not adequately controlled by over-the-counter antihistamines, or if you develop swelling of the skin without a rash. Assessment is also relevant if you suspect a specific trigger and would like to have it confirmed or ruled out.
A rash that remains in the same place for several days is rarely urticaria and may, for example, be eczema.
How are hives assessed by a dermatologist?
The assessment is based primarily on your medical history: when the rash started, how long the wheals last, whether there is swelling, and whether anything specific seems to trigger the symptoms, such as cold, pressure, exercise, medication or food. Bringing photos of the rash is very helpful because it may have disappeared by the day of the consultation. Keeping a diary of flare-ups can also provide important clues.
The skin is then examined. Depending on the medical history, blood tests may be taken, and if allergy is suspected, skin prick testing can be performed at the clinic.
In chronic urticaria, the main purpose of the assessment is to rule out other conditions, identify possible triggers and evaluate how much the condition affects everyday life so that treatment can be tailored accordingly.
The assessment is carried out by Susanne Birkballe, specialist in dermatology.
Hives in children
Hives are common in children and are usually acute and triggered by an infection. The rash may look alarming, but it is generally harmless and clears up on its own within days to weeks. If it lasts longer or keeps coming back, the child should be examined.
The dermatologist sees children of all ages. If a food allergy is suspected, it may also be appropriate to see a pediatrician.
Referrals and payment
Many health insurance policies cover a consultation with a dermatologist, but insurers typically require a referral from your GP and prior approval. No referral is needed if you are paying for treatment yourself. Prices are listed on the price list. Consultations take place at the main clinic in Charlottenlund.
Frequently asked questions
Are hives contagious?
No. Hives are not contagious. If they are triggered by an infection, the infection itself may be contagious, but the rash is not.
How long do hives last?
Acute hives last less than 6 weeks and often just a few days. Chronic hives last more than 6 weeks and may come and go for months or years, but for many people they become milder over time.
Can stress cause hives?
Stress can make chronic hives worse, but is rarely the only cause. A dermatologist’s assessment considers all possible triggers.
Are hives caused by allergy?
Acute hives can be caused by an allergic reaction, for example to a food or medication. Chronic hives are rarely caused by an allergy. If an allergy is suspected, a skin prick test can be performed.
When should you call 112 for hives?
Call 911 for difficulty breathing, difficulty swallowing, swelling of the tongue or throat, or dizziness, as these may be signs of a severe allergic reaction.
Do you need a referral to see a dermatologist for hives?
If you are paying privately, you do not need a referral. If you are using health insurance, the insurer will typically require a referral from your GP and prior authorisation.
Read also
Hives may be confused with or associated with other conditions:
→ Dermatologist and dermatology – Overview of skin conditions → Allergy –Skin prick testing and allergy assessment → Eczema – Itchy rashes that remain in the same place → Food allergy in children –Symptoms and testing