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Help for Hives has been created and funded by Novartis Pharmaceuticals UK Ltd.

What is urticaria?

Urticaria, also known as hives, are itchy, raised patches on the skin. Varying in shape, size and colour, they can appear anywhere on your body. They are often extremely itchy and can cause a burning or stinging sensation. Many people with urticaria also experience skin swelling, known as angioedema, which most commonly affects the eyes, lips, face, genitals, hands and feet.
Urticaria does not usually affect general health, but the appearance of the rash and the itch itself can be extremely distressing. However, as a rule, urticaria tends to improve and become less troublesome over time. Individual hives can clear within 24 hours, but the overall rash may last longer.

What is urticaria?
What is CSU?

What is CSU?

CSU is a spontaneous disease that on average lasts up to five years, but sometimes patients suffer for much longer.2 Linked to the immune system3,4, CSU not only affects the skin but can also have a huge impact on patients’ mental health.5 CSU should be managed in consultation with a doctor, and with treatment, symptoms may be alleviated which may restore quality of life.

Is CSU caused by an allergy?

No, CSU is not caused by an allergy. Unfortunately, the cause of the histamine release in CSU remains unknown, hence the term ‘chronic spontaneous urticaria’.


What causes CSU and urticaria?


The causes of CSU are unknown. The redness, swelling and intense itching and/or burning associated with the condition occurs when immune cells are stimulated, causing the body to release certain chemicals in an abnormal way, making blood rush to the skin.7

what causes



The physical symptoms of urticaria are caused by triggers which raise the levels of histamine, a chemical released from mast cells which is a type of white blood cell within your immune system. Mast cells are abundant not only in the skin but also in tissues such as the tongue and lips. They are located close to blood vessels and contain high amounts of histamine and various other chemicals. When mast cells release histamine, the local blood vessels widen and increase blood flow to the area. Histamine also stimulates local nerves in the skin, causing itching and occasionally pain.

Triggers can include:6

  • eating certain foods

  • contact with certain plants, animals, chemicals and latex

  • cold – such as cold water or wind

  • hot, sweaty skin – from exercise, emotional stress or eating spicy food

  • a reaction to a medicine, insect bite or sting

  • scratching or pressing on your skin – such as wearing itchy or tight clothing

  • an infection

  • a problem with your immune system

  • water or sunlight – but this is rare


What are the symptoms of urticaria and CSU?

Symptoms of urticaria are itchy, raised patches on the skin that can vary in shape, size and colour. They can appear anywhere on your body and can sometimes be painful.8

Many people with urticaria also experience pronounced swelling of the deeper layers of the skin. This is called angioedema, and most commonly affects the eyes, lips, face, genitals, hands and feet.9 Angioedema can often be mistaken for anaphylaxis, a severe allergic reaction. 

Some people with CSU may experience anxiety or depression.10 This is often due to the unpredictable nature of the disease such as when a flare-up will occur and for how long it will last. This may affect different aspects of life such as work, sleep and relationships. Therefore, it is important to see a doctor who can work with you to understand and help manage your condition.

Many people with CSU live with symptoms for up to two years or more before receiving a correct diagnosis, so if your symptoms don’t clear up in six weeks it is worth seeking medical advice as soon as possible.11,12

How long do the symptoms last?

How long your symptoms last will depend on the type of urticaria you have. Due to the spontaneous nature and difficulty pinpointing the triggers of CSU, it is a good idea to measure your symptoms for factors like duration, size and shape and itchiness or pain.

The aim of urticaria and CSU treatment is to suppress the symptoms of the condition so that it can heal naturally, rather than be cured. In about 50% of CSU cases, the rash lasts for 6-12 months with appropriate treatment.13

Urticaria can differ in duration and cause14


The above diagram is not a diagnosis tool but only a guide. If you think you might have any of the conditions mentioned above, you should seek medical advice from your doctor.

Measure your urticaria impact

Take control of your treatment journey with HiveHelper

To help your doctor find the best treatment for you, it is really important to measure your condition regularly.  HiveHelper is our virtual companion to help you learn more about urticaria and CSU.

HiveHelper is only currently available if you have Facebook Messenger. We are working on another way for those without Facebook to access the virtual companion tool. If you don’t have Facebook, you can download our interactive PDF resources here, which you can use to measure the impact of urticaria and CSU.

Mast cells – the science behind urticaria and CSU

CSU is an internal disease linked to an overactive immune system.

1. Your immune system protects you from unfamiliar things and includes many key players: ​​​​
- Immunoglobulin E or IgE
  Immunoglobulin E (IgE) are antibodies produced by the immune system.
- Mast cells
  A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin.
- Basophils
  Basophils are one of the several kinds of white blood cells you have in your body. Basophils are a part of your immune system and are created inside of your bone marrow. They are found in tissues where allergic reactions occur.

What happens with CSU?
2. In the presence of allergens, IgE binds to mast cells and basophils

3. Allergens bind to IgE present on mast cells and basophils
- When IgE on mast cells and basophils are activated by an allergen, powerful mediators such as histamine are release
- This leads to a physical inflammatory reaction on the skin

How your body responds to histamine and other mediators
- Itching    - Redness    - Hives    - Angiodema 

Mast Cells Diagram Key
Mast Cells 1 and 2
Mast Cells 3

How they differ from other skin diseases


Hives rashes usually settle down within a few minutes to a few days. You can often treat hives yourself. They can be different sizes and shapes and appear anywhere on the body in both adults and children.

  • Hives can appear as raised patches of skin.
  • The rash can be red. Redness can be harder to see on darker skin.
  • The rash can also be raised spots.
  • The rash is often itchy and sometimes feels like it’s stinging or burning.


Acne is a common skin condition that affects most people at some point. It causes spots, oily skin and sometimes skin that’s hot or painful to touch. Acne most commonly develops on the face, back and chest.
There are 6 main types of spots caused by acne:

  • blackheads – small black or yellowish bumps that develop on the skin; they’re not filled with dirt, but are black because the inner lining of the hair follicle produces colour
  • whiteheads – have a similar appearance to blackheads, but may be firmer and will not empty when squeezed
  • papules – small red bumps that may feel tender or sore
  • pustules – similar to papules, but have a white tip in the centre, caused by a build-up of pus
  • nodules – large hard lumps that build up beneath the surface of the skin and can be painful
  • cysts – the most severe type of spot caused by acne; they’re large pus-filled lumps that look similar to boils and carry the greatest risk of causing permanent scarring


  • Atopic eczema (atopic dermatitis) is the most common form of eczema, a condition that causes the skin to become itchy, dry and cracked.
  • Atopic eczema causes the skin to become itchy, dry, cracked and sore.
  • Some people only have small patches of dry skin, but others may experience widespread inflamed skin all over the body.
  • Although atopic eczema can affect any part of the body, it most often affects the hands, insides of the elbows, backs of the knees and the face and scalp in children.
  • People with atopic eczema usually have periods when symptoms are less noticeable, as well as periods when symptoms become more severe (flare-ups).

Actinic keratosis¹⁷

Actinic keratoses (also called solar keratoses) are dry scaly patches of skin that have been damaged by the sun.
The patches:

  • can feel dry, rough and scaly, or like sandpaper
  • are usually between 1cm to 2cm in size
  • can be the same colour as your skin or range from pink to red to brown
  • may feel itchy


Rosacea is a long-term skin condition that mainly affects the face. It’s more common in women and people with lighter skin, but symptoms can be worse in men. Treatment can help with symptoms.
As rosacea gets worse, your cheeks, nose, skin and forehead will be red all the time.
Tiny broken blood vessels that do not go away may appear on your skin.
You may get small pink or red bumps. Sometimes these become filled with a yellowish liquid.
Other symptoms can include:

  • dry skin
  • swelling, especially around the eyes
  • yellow-orange patches on the skin
  • sore eyelids or crusts around roots of eyelashes – this could be blepharitis
  • thickened skin, mainly on the nose (usually appears after many years)


  • Psoriasis is a skin condition that causes red, flaky, crusty patches of skin covered with silvery scales.
  • These patches normally appear on your elbows, knees, scalp and lower back, but can appear anywhere on your body. 
  • Most people are only affected with small patches. In some cases, the patches can be itchy or sore.


Cellulitis is a skin infection that’s treated with antibiotics. It can be serious if it’s not treated quickly.
Cellulitis makes your skin painful, hot and swollen. The area usually looks red, but this may be less obvious on darker skin tones.
Your skin may also be blistered, and you can also have swollen, painful glands.
You can get cellulitis on any part of your body, such as:

  • Hands - causing swelling in your fingers or the back of your hand.
  • Feet – sometimes near toes if you have athlete’s foot.
  • Legs – usually the lower legs.
  • Eyes – the white part of your eye may become red, but this does not always happen.


  • Measles is an infection that spreads very easily and can cause serious problems in some people. 
  • Measles usually starts with cold-like symptoms, followed by a rash a few days later. Some people may also get small spots in their mouth.
  • A rash usually appears a few days after the cold-like symptoms.
  • The spots of the measles rash are sometimes raised and join together to form blotchy patches. They’re not usually itchy.

Basal cell carcinoma²²

  • Basal cell carcinoma (BCC) usually appears as a small, shiny pink or pearly-white lump with a translucent or waxy appearance. It can also look like a red, scaly patch.
  • There’s sometimes some brown or black pigment within the patch.
  • The lump slowly gets bigger and may become crusty, bleed or develop into a painless ulcer.


  • Lupus is a long-term condition that causes joint pain, skin rashes and tiredness. There’s no cure, but symptoms can improve if treatment starts early.
  • Symptoms include inflammation of different parts of the body including the lungs, heart, liver, joints and kidneys.
  • Lupus often flares up (relapses) and symptoms become worse for a few weeks, sometimes longer.
  • Symptoms then settle down (remission). The reason why symptoms flare up or settle down is not known.
  • Some people do not notice any difference and their symptoms are constant.

Contact dermatitis²⁴

  • Contact dermatitis is a type of eczema triggered by contact with a particular substance.
  • Contact dermatitis causes the skin to become itchy, blistered, dry and cracked.
  • Lighter skin can become red, and darker skin can become dark brown, purple or grey.
  • This reaction usually occurs within a few hours or days of exposure to an irritant or allergen.
  • Symptoms can affect any part of the body but most commonly the hands and face.

Keratosis pilaris²⁵

Keratosis pilaris is a very common harmless condition where small bumps appear on your skin. It can last for a long time, but there are treatments that may improve your skin.
Symptoms can include:

  • Dry, rough skin
  • Small, painless bumps on your skin


Impetigo is a skin infection that’s very contagious but not usually serious. Anyone can get it, but it’s very common in young children.
Impetigo starts with red sores or blisters, but the redness may be harder to see in darker skin tones.
The sores or blisters quickly burst and leave crusty, golden-brown patches.
The patches can:

  • look a bit like cornflakes stuck to your skin
  • get bigger
  • spread to other parts of your body
  • be itchy
  • sometimes be painful

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UK  |  June 2022  |  204803


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  2. Maurer M, et al. Unmet clinical needs in chronic spontaneous urticaria. A GA2LEN task force report. Allergy 2011;66(3):317–330;

  3. Navinés-Ferrer, Serrano- Candelas E, Molina-Molina GJ, et al. IgE-Related Chronic Diseases and Anti-IgE-Based Treatments. J Immunol Res 2016;2016:8163803

  4. Puxeddu I, et al. Mediators Inflamm. 2017;4123694; 

  5. Balp MM, et al. J Eur Acad Dermatol Venereol. 2018;32(2):282-290 

  6. NHS. Hives. Available online at: [Last accessed: April 2022]

  7. Zuberbier T, et al. Allergy. 2014;69(7):868-887 

  8. NHS Inform. Urticaria (Hives). Available online at: [Last accessed: April 2022]

  9. NHS Inform. Angiodema. Available online at: [Last accessed: April 2022]

  10. Powell R, Leech S, Till S, BSACI guideline for the management of chronic urticaria and angioedema. Clinical & Experimental Allergy 2015 (45) 547–565 

  11. Novartis and Allergy UK. Wheals of despair [online] June 2014. Available from: [Last accessed: April 2022] 

  12. Maurer M, Abuzakouk M, Bérard F, et al. The burden of chronic spontaneous urticaria is substantial: Real-world evidence from ASSURE-CSU. Allergy 2017;72:2005–2016. 

  13. British Skin Foundation. Urticaria and Angioedema. Available online at: [Last accessed: April 2022]

  14. Dressler, C. et al (2018). Chronic inducible urticaria: a systematic review of treatment options. Journal of Allergy and Clinical Immunology, 141(5), 1726-1734. 

  15. NHS. Acne Overview. Available online at: [Last accessed: April 2022]

  16. NHS. Atopic Eczema Overview. Available online at: [Last accessed: April 2022]

  17. NHS. Actinic Keratoses Overview. Available online at: [Last accessed: April 2022]

  18. NHS. Rosacea Overview. Available online at: [Last accessed: April 2022]

  19. NHS. Psoriasis Overview. Available online at: [Last accessed: April 2022]

  20. NHS. Cellulitis Overview. Available online at: [Last accessed: April 2022]

  21. NHS. Measles Overview. Available online at: [Last accessed: April 2022]

  22. NHS. Non-Melanoma Skin Cancer Overview. Available online at: [Last accessed: April 2022]

  23. NHS. Lupus Overview. Available online at: [Last accessed: April 2022]

  24. NHS. Contact Dermatitis Overview. Available online at: [Last accessed: April 2022]

  25. NHS. Keratosis Pilaris Overview. Available online at: [Last accessed: April 2022]

  26. NHS. Impetigo Overview. Available online at: [Last accessed: April 2022]

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