Pictures to Help With Identifying Hives vs. Other Skin Rashes

Hives, also known as urticaria, are a type of skin rash with raised, red, itchy bumps or welts. Hives are a common condition that affects up to 20% of the population at one time or another.

Hives can affect any person at any age on any part of the body in any season of the year. They can be as size as the tip of a pen or as large as a dinner plate. Hives can also cause stinging or burning sensations. The itching is typically worse at night and can interfere with sleep.

In this gallery of images, you will view several types of hives and the important characteristics of each. The article will also explain why different hives develop and what can be done to treat them.

Hives Caused by Infection

Close-Up of Hives Caused By Infection

Heather L. Brannon, MD

Hives are often idiopathic, meaning that they can develop spontaneously for no known reason.

If a cause can be found, it is most often the result of a reaction to one of the following:

  • Allergic reactions to food, medications, or insect bites
  • Bacterial or viral infections, including strep throat, colds, and mononucleosis
  • Physical triggers like cold temperatures, pressure, scratching, or vibrations
  • Sweating events like exercise or being in an overheated environment
  • Psychological stress
  • Sun exposure (uncommon)
  • Water exposure (uncommon)

This photo is an example of hives caused by a ​viral infection. Hives caused by an infection tend to be generalized (widespread) rather than localized (as can occur with things like a bug bite).

Recap

Common causes of hives include allergies and infections. Certain physical triggers like extreme cold, vibration, or exercise can also cause hives. Less common causes include sun or water exposure.

Chronic Hives

Hives
anand purohit / Getty Images

Hives can usually be diagnosed based on their appearance. The hives may be acute, meaning that they develop rapidly and tend to resolve quickly. They may also be chronic, meaning that they persist for more than six weeks and/or recur frequently over months or years.

Chronic hives are most often idiopathic and will develop spontaneously for no apparent reason. It is thought that some sort of autoimmune disorder may be involved.

Chronic hives may also be inducible, meaning that a known trigger causes them. One such example is hives that develop after wearing a tight belt or clothing, referred to as pressure-induced urticaria.

People with chronic hives tend to have co-occurring atopic (allergy-related) conditions like asthma, atopic dermatitis (eczema), and allergic rhinitis (hay fever).

Chronic hives tend to cause splotchy welts, as in this picture, with raised edges and defined borders.

Recap

Chronic hives are those that last for more than six weeks and/or recur frequently over the course of months or years. Most cases of chronic hivesare idiopathic (of unknown origin).

Acute Hives

Urticaria Rash (Hives) On Legs Due to Exam Stress

DR P. MARAZZI / SCIENCE PHOTO LIBRARY / Getty Images

Acute hives are common and tend to be harmless, Most clear up within a day and don't leave any lasting marks. This is a picture of acute hives.

A doctor may prescribe an oral antihistamine to help relieve the itching or recommend simple home remedies to help relieve the discomfort. Fortunately, most cases resolve on their own.

This doesn't mean that all cases of acute hives are harmless. If hives develop suddenly and are accompanied by shortness of breath, wheezing, and the swelling of the face or tongue, it could be a sign of a potentially life-threatening, whole-body allergy known as anaphylaxis.

Other signs of anaphylaxis include dizziness, irregular heartbeats, and a feeling of impending doom. 911 emergency assistance is needed.

Recap

Call 911 if acute hives are accompanied by shortness of breath, wheezing, dizziness, irregular heartbeat, and swelling of the face or tongue. These are all signs of a medical emergency known as anaphylaxis.

Spongy Hives

Close-Up of Spongy Hives

Heather L. Brannon, MD



Hives are caused when the immune system responds abnormally to certain physical, environmental, and even psychological triggers.

When this happens, the immune system will instruct immune cells in the skin (called mast cells) and immune cells in the blood (called basophils) to break open and release inflammatory chemicals, including histamine, into the body.

Histamine causes tiny blood vessels in the skin to widen in order for larger immune cells to access the site of the supposed injury. The widening causes fluids to leak into surrounding tissues, causing the raised, red welts we recognize as hives.

Depending on the amount of fluid that gets released, hives can look very "spongy" like this. Or, they can appear flat with well-defined, raised borders.

Recap

Hives are mainly due to the release of a chemical known as histamine by the immune system. Histamine causes blood vessels in the skin to widen and leak fluid into surrounding tissues, resulting in raised, itchy hives.

Dermatographism

Appearance of the word "Dermatographia" on a human arm 15 minutes after the letters have been traced with a blunt object on the skin. A type of urticaria or "hives", also known as dermatographic urticaria, dermatographism, or "skin writing".
R1carver/Wikimedia Commons/CC-BY-SA-3.0

When people refer to hives, they often think of an allergic response to food or medications. But, hives can also be caused by physical stimuli that cause the skin to form raised, red welts.

One example is dermatographism. Dermatographism is a form of chronic urticaria caused by stroking the skin with pressure. The term "dermatographism" literally means the ability to write on the skin.

Dermatographism is among the most common forms of hives, affecting anywhere from 2% to 5% of the world's population. Even so, the exact cause of this condition is largely unknown.

Similar conditions include cold-induced urticaria, pressure-induced urticaria, exercise-induced urticaria, and stress-induced urticaria.

Recap

Physical stimuli can trigger hives in some people. The cause of this is largely unknown. Triggers can include cold, pressure, exercise, stress, or scratching (referred to as dermatographism).

Summary

Hives (urticaria) are a type of rash that causes raised, red, itchy bumps or welts. Hives may be acute, appearing quickly and usually resolving quickly on their own. Or, they may be chronic, lasting for more than six months and/or recurring frequently over months or years.

There are many possible causes of hives, including allergies, infections, stress, cold, vibration, exercise, and even scratching. Chronic hives are often idiopathic, meaning of unknown origin, and may develop spontaneously for no apparent reason.

Hives are ultimately caused by an abnormal immune response in which inflammatory chemicals, including histamine, are released into the bloodstream and tissues. Antihistamines may be used to relieve the swelling, redness, or itchiness of hives. Many cases clear up on their own without treatment.

Frequently Asked Questions

  • Can emotional stress cause hives?

    Yes. Histamine can cause puffy, red, raised welts known as hives. The sympathetic nervous system churns out histamine when we are under stress—the same chemical responsible for an allergic reaction.

  • What is the difference between a rash and hives?

    Rash is an umbrella term for red, itchy, and irritated skin. Hives are a type of rash that causes raised, red, and often itchy bumps.

  • How long do hives last?

    Without treatment, hives can last for a few days. Taking an oral antihistamine, like Benedryl, or applying a topical treatment can help hives to clear up sooner. You can also use a cold compress to calm the itch.

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8 Sources
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  1. Sachdeva S, Gupta V, Amin SS, Tahseen M. Chronic urticariaIndian J Dermatol. 2011;56(6):622–628. doi:10.4103/0019-5154.91817

  2. Wedi B, Raap U, Wieczorek D, Kapp A. Urticaria and infectionsAllergy Asthma Clin Immunol. 2009;5(1):10. doi:10.1186/1710-1492-5-10

  3. Kanani A, Betschel SD, Warrington R. Urticaria and angioedemaAllergy Asthma Clin Immunol. 2018;14(Suppl 2):59. doi:10.1186/s13223-018-0288-z

  4. Jain S. Pathogenesis of chronic urticaria: an overviewDermatol Res Pract. 2014;2014:674709. doi:10.1155/2014/674709

  5. Schoepke N, Doumoulakis G, Maurer M. Diagnosis of urticariaIndian J Dermatol. 2013;58(3):211–218. doi:10.4103/0019-5154.110831

  6. Yadav S, Bajaj AK. Management of difficult urticariaIndian J Dermatol. 2009;54(3):275–279. doi:10.4103/0019-5154.55641

  7. Branco ACCC, Yoshikawa FSY, Pietrobon AJ, Sato MN. Role of Histamine in Modulating the Immune Response and InflammationMediators Inflamm. 2018;2018:9524075. doi:10.1155/2018/9524075

  8. Nobles T, Schmieder GJ. Dermatographism. In: StatPearls [Internet]. Tampa FL: StatPearls Publishing; 2022.