Why Do I Randomly Get Hives?

Hives are a common unpleasant skin reaction that can occur randomly or in response to specific triggers such as allergens, stress or illness. In repsonse to the triggers cause the body to release histamine, which gives way to a red, itchy and sometimes burning rash. If you frequently experience hives, it may be helpful to see a healthcare provider to determine the underlying cause and develop a treatment plan.

What are hives?

Urticaria is a skin condition characterised by the development of wheals (hives), angioedema or both. Hives are commonly associated with a red, raised and intensely itchy rash.1

Wheals in patients with urticaria can typically be identified with three features:1

  1. An itchy sensation, sometimes one that burns
  2. A central swelling of varying sizes, typically accompanied by reflex erythema (skin response causing blood vessels in the skin to dilate, resulting in the reddening of the skin)
  3. A fleeting nature

Hives can occur anywhere on the body and often differs in shape and size. While hives can be a nuisance, the rash usually disappears within a few minutes to a few days. The underlying causes may be complex and diverse, including allergies, infections, physical triggers and autoimmune disorders. Hives are generally harmless and can be treated with over-the-counter medications. In this article, we will explore why some individuals may randomly get hives.2

The development of hives is attributed to an allergic reaction in the body. The allergic reaction releases histamine and other chemicals into the bloodstream, resulting in the characteristic raised red and itchy welts commonly associated with hives. Hives can be acute (lasting less than six weeks), commonly due to an allergic reaction triggered by specific allergens such as particular food, medications, or insect bites. Acute hives may occur unexpectedly ( a phenomenon known as spontaneous or idiopathic urticaria which can occur in response to a physical stimulus.

On the other hand, chronic hives (longer than six weeks) can be more challenging to diagnose and treat and may be caused by an underlying medical condition.2 33-50% of all chronic urticaria cases are thought to be of the autoimmune type (when the body's immune system attacks its tissues).3,4,5

Angioedema is a more severe type of urticaria that frequently affects the hands, feet, lips, eyelids and genitals. It causes rapid but temporary swellings of deeper dermal and subcutaneous tissues. In 40-50% of cases, angioedema and urticaria can co-occur, although either symptom can also occur on its own.3

Causes of Hives?

What are the most common causes of hives, and why can I get them randomly?

Hives is a mast-cell (white blood cell found in connective tissue) driven disease. When white blood /cells and their histamine are produced from under the skin's surface, swelling of the tissues results in hives. There are many reasons why an individual may develop hives. Some of the most common causes include:1,4

  • Allergic Reactions - The most common cause for hives, which involves a physiological reaction to a particular allergen, which may include foods such as milk, eggs, peanuts, tree nuts, or shellfish4
  • Stress: Stress is another common trigger for hives; it can cause the release of certain hormones in the body, which leads to the manifestation and development of hives1
  • Physical Triggers: Certain physical triggers can cause hives to develop. These include exposure to heat or cold, pressure on the skin, and exposure to water or UV from sunlight1,4
  • Infections: In some cases, hives may develop due to an infection in the body. Both acute and chronic infections can cause hives (e.g. Helicobacter pylori or Anisakis simplex). Anisakis simplex, a sea fish nematode, has been suggested as a possible cause of recurrent acute spontaneous urticaria, especially prevalent in areas where raw fish is eaten regularly1
  • Genetics: In some cases, hives may be hereditary, and individuals may be more prone to developing them if they have a family history of the condition6,7
  • Autoimmune Disorders: Certain autoimmune disorders, such as Systemic lupus erythematosus (SLE), dermatomyositis or ‘Still disease’, have been associated with the presentation of hives8

How are hives diagnosed?

Generally, a diagnosis is unnecessary for acute urticaria as the condition will be resolved independently (a self-limiting condition). However, it would be wise to investigate the chance of acute urticaria caused being caused a type I food allergy in sensitised patients or if there are other triggers, such as nonsteroidal anti-inflammatory drugs (NSAIDs). In these patients, allergy testing and the proper education for patients can be beneficial in helping patients determine and avoid the eliciting factors causing the condition.1


While it may not be possible for hives to develop completely, there are several steps you can take to reduce the risk of getting hives. Some are listed below:1,2

  • Avoid known allergens: If you know what can cause hives, then make an effort to avoid these known triggers as much as possible
  • Manage stress: Since stress is a known trigger for hives, find ways to manage and reduce stress levels, such as exercise, therapy, meditation and eating a healthy, well-balanced diet
  • Adhere to prescribed medications: Your doctor will diagnose you, and your prescription will be tailored to your condition, so it is important to ensure that you take the medication exactly as prescribed by your doctor
  • Protect yourself against contact triggers: Wear loose-fitting, comfortable clothing if tight pressure triggers hives. ear a UV-blocking sunscreen to protect against sunlight as prolonged esposure could trigger hives
  • Use cool compresses: To reduce reddness and swelling, a cold compress may be placed on the affected area which may also help with the itching
  • Talk to your doctor: If you are experiencing recurring or severe hives, discuss possible underlying causes and treatment options with your physician. If necessary, your doctor may even refer you to a specialist physician (e.g. an allergist)

Treatment options for hives?

For hives, the basic principle for pharmacological treatment is to control the condition and provide symptom relief. There are some medical treatment options for patients, which include the following:1

  • Antihistamines: Antihistamines are often the first line of treatment for hives; their use is not only supported in clinical trials but also with its mechanism of action (how the drug works). They work by blocking the effects of histamine, which is the chemical released by the body in response to an allergen or other trigger that causes hives. Some common antihistamines include cetirizine, desloratadine, and fexofenadine1,7
  • Corticosteroids: Corticosteroids can be used to reduce inflammation and swelling associated with severe cases of hives. They have good efficacy during intake and are widely available, but they are unsuitable for long-term therapy as they can have side effects1
  • Topical creams and ointments: Topical creams and ointments that may contain menthol, camphor, or capsaicin can be used to relieve itching and discomfort associated with hives2,9,10
  • Avoidance of triggers: If the hives are caused by an allergen or other trigger, avoiding that trigger is the best course of action to prevent future outbreaks1
  • Immunosuppressants: Other treatment options may include immunosuppressant medications such as methotrexate, mycophenolate mofetil or azathioprine. These may be prescribed to control chronic hives that do not respond to other treatments7

What do the clinical guidelines state?

Guidelines developed by the European Academy of Allergy and Clinical Immunology (EAACI), the Global Allergy and Asthma European Network (GA²LEN), the European Dermatology Forum (EDF) and the World Allergy Organization (WAO), recommend the following:7

  •  First-line treatment: the use of second-generation H1 antihistamines as a treatment for urticaria, including hives7
  • Second-line treatment: If symptoms persist for an additional 1-4 weeks, then the dose of the second-generation H1 antihistamines is increased by four7
  • Third-line treatment: Patients may be prescribed omalizumab, montelukast or cyclosporine. If symptoms are unsuccessfully controlled, corticosteroid therapy may be used for up to 10 days7

In addition, the guideline notes that newer, second-generation antihistamines such as cetirizine, loratadine, and fexofenadine are generally preferred over older, first-generation antihistamines due to their improved efficacy and better long-term safety profile.7

When to seek medical attention?

It's important to note that treatment for hives will vary depending on the severity and underlying cause of the condition. As stated above, the condition may clear up on its own. However, if you are concerned with how the rash looks, if it persists longer than expected or seems to be worsening, then it's always best to consult a healthcare professional for a proper diagnosis and treatment plan.

Additionally, if hives is accompanied by difficulty breathing, swelling of the face/throat or a fever, then it is important to contact your doctor as it may be a sign of a more severe condition, such as anaphylaxis.2


In summary, hives are a form of urticaria caused by various factors, including allergies, stress, infections, and autoimmune diseases. Occasionally, the cause of hives is unknown, but it can still be treated effectively. 

There are many treatment options for hives, including topical ointments, antihistamine medication and corticosteroid therapy. It is also crucial to recognise known triggers, such as certain food, medication or environmental factors, and to avoid them. Finally, identifying and addressing the underlying cause of hives, whether through medication or lifestyle changes, will successfully eliminate hives and prevent their recurrence! 


  1. Zuberbier T, Aberer W, Asero R, Abdul Latiff AH, Baker D, Ballmer-Weber B, et al. The EAACI/GA2LEN/EDF/WAO guideline for the definition, classification, diagnosis and management of urticaria. Allergy. 2018 Jul;73(7):1393–414. 
  2. Hives [Internet]. nhs.uk. 2017 [cited 2023 Mar 25]. Available from: https://www.nhs.uk/conditions/hives/
  3. Bernstein JA, Lang DM, Khan DA, Craig T, Dreyfus D, Hsieh F, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. Journal of Allergy and Clinical Immunology [Internet]. 2014 May 1 [cited 2023 Mar 25];133(5):1270-1277.e66. Available from: https://www.jacionline.org/article/S0091-6749(14)00335-2/fulltext
  4. Hide M, Takahagi S, Hiragun T. Urticaria and angioedema. In: Kang S, Amagai M, Bruckner AL, Enk AH, Margolis DJ, McMichael AJ, et al., editors. Fitzpatrick’s Dermatology [Internet]. 9th ed. New York, NY: McGraw-Hill Education; 2019 [cited 2023 Mar 25]. Available from: accessmedicine.mhmedical.com/content.aspx?aid=1161329915
  5. Hives (Urticaria) | causes, symptoms & treatment [Internet]. ACAAI Public Website. [cited 2023 Mar 25]. Available from: https://acaai.org/allergies/allergic-conditions/skin-allergy/hives/
  6. D.O PH. Chronic hives are becoming the most common of all auto-immune disease [Internet]. Allergy Center of Connecticut. 2018 [cited 2023 Mar 25]. Available from: https://allergyct.com/hives/chronic-hives-are-becoming-the-most-common-of-all-auto-immune-disease/
  7. Kayiran MA, Akdeniz N. Diagnosis and treatment of urticaria in primary care. North Clin Istanb [Internet]. 2019 Feb 14 [cited 2023 Mar 25];6(1):93–9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6526977/
  8. Konstantinou GN, Asero R, Ferrer M, Knol EF, Maurer M, Raap U, et al. EAACI taskforce position paper: evidence for autoimmune urticaria and proposal for defining diagnostic criteria. Allergy. 2013 Jan;68(1):27–36. Camphor and menthol topical uses, side effects & warnings [Internet]. Drugs.com. [cited 2023 Mar 25]. Available from: https://www.drugs.com/mtm/camphor-and-menthol-topical.html
  9. Lysy J, Sistiery-Ittah M, Israelit Y, Shmueli A, Strauss-Liviatan N, Mindrul V, et al. Topical capsaicin—a novel and effective treatment for idiopathic intractable pruritus ani: a randomised, placebo controlled, crossover study. Gut [Internet]. 2003 Sep [cited 2023 Mar 25];52(9):1323–6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1773800/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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