Hives, medically termed urticaria, are skin rashes characterized by itchy, raised bumps on the skin. They are often due to an allergic reaction but not always. In some cases, hives may be associated with an underlying medical condition or other stimuli. Individual hives usually last less than 24 hours, but in some cases, they can last longer.
This article includes pictures of hives, their types, what causes them, and how they are treated.
Table of Contents
What are hives?
Hives, also known as welts and wheals, are raised bumps on the skin. They often appear as random, itchy bumps that come and go, and are usually a result of the body’s reaction to certain elements. They can appear anywhere on the body, such as the face, neck, arms, hands, legs, chest, and back.
Are they contagious?
Hives themselves are not contagious and cannot spread through touch. However, if they occur due to an infection or contact with a certain chemical, that infection or chemical can, in some cases, be spread by contact.
Hives vs. rash
A rash refers to an inflamed or irritated area of the skin that appears different in color or texture compared to the rest of the skin. There are different kinds of rashes, and hives are one of them. In other words, hives are a type of skin rash, but not every rash is hives. Read more details about the difference between hives and rashes here.
Pictures
The pictures below show hives rash on various parts of the body, including the face, arms, back, and in different skin tones.
The picture below shows dermatographism, which is a type of chronic inducible urticaria (details later in the article).
What do they look like?
Hives are characterized by the following features:
- Shape: Hives can be round, oval, ring-shaped, or irregular, sometimes resembling a map or a splotch.
- Size: These can range from a few millimeters to several centimeters. Smaller spots can come together to form a large plaque.
- Color: The color can vary depending on skin tone. In lighter skin tones, hives can appear pink, red, or skin-colored, whereas in darker skin, they might appear purplish or darker than the surrounding skin. They are often surrounded by a zone of redness, giving the appearance of a red flare.
- Blanchable: Another feature of hives is that when pressed, they become pale or white in appearance, a phenomenon known as blanching.
- Surface: These welts are usually smooth, with a slightly raised, swollen appearance.
- Arrangement: Hives can occur singly or in clusters. They can merge to form larger spots.
- Changes over time: One important feature of hives is their ability to change shape and location over a short period. A welt might appear in one place, then vanish, only to reappear in another area, especially in chronic hives.
- Duration: The duration of a hive can vary depending on the type. Acute hives usually last less than 24 hours (often 2–3 hours), while chronic hives last longer.
Associated symptoms
Hives are usually very itchy. They can also cause a burning or stinging sensation. The level of itchiness can vary and may be more intense at certain times.
Types and causes
Hives can be classified based on duration into two main types: acute and chronic. The underlying causes of these types can vary.
1. Acute urticaria
Acute hives last less than six weeks. These hives are often due to an allergic reaction where the body releases histamine and other inflammatory mediators, such as cytokines, into the blood.
This release is the body’s response to what it perceives as harmful substances, even though they are not harmful to most people. Below are some of the common triggers:
- Foods such as nuts, shellfish, eggs, milk, and strawberries.
- Food additives and preservatives.
- Medications include antibiotics (especially penicillin and sulfa drugs), painkillers like aspirin and ibuprofen, and blood pressure medications.
- Insect bites and latex.
- Environmental factors, including pollen, animal dander, and other environmental allergens.
- Stress.
- Exposure to chemicals, whether in the workplace or from everyday products.
- Infections.
2. Chronic urticaria
Chronic hives persist for more than six weeks and can last much longer. According to one study, more than 50% of patients with chronic hives recovered or improved spontaneously within a year.
These can be continuous, where they keep appearing on the body, or intermittent, where they disappear only to reappear later. Compared to acute hives, chronic hives are usually not due to allergic reactions.
Chronic urticaria can be further divided into spontaneous and inducible types.
Chronic spontaneous urticaria
The exact cause behind this type is often unknown (sometimes referred to as the idiopathic type). It may be associated with underlying health issues such as infections, stress, or autoimmune disorders where our immune system attacks our organs, such as thyroid disorders, lupus, or rheumatoid arthritis.
Chronic inducible urticaria
This type of urticaria occurs in response to a stimulus, which can be physical or non-physical. Hives can be localized to the area of the stimulus or can be more widespread.
There are several types of chronic inducible urticaria which include:
- Dermatographism: This is the most common type and is triggered by scratching or firm stroking of the skin. The hives often appear as red streaks within minutes and resolve quickly.
- Delayed-pressure urticaria: This type is caused by pressure on the skin, such as from tight clothing, belts, or prolonged sitting or standing. The hives usually appear a few hours after the application of pressure.
- Exercise-induced urticaria: This type is triggered by exercise. In comparison to cholinergic urticaria, the wheals are larger, and it is not triggered by other stimuli.
- Cold urticaria: Caused by exposure to cold temperatures.
- Heat urticaria: It leads to localized hives within minutes following direct exposure to heat.
- Solar urticaria: This type is triggered by exposure to UV light from the sun or other sources.
- Vibratory urticaria: It is triggered by vibration and affects the exposed area, often the hands.
- Cholinergic urticaria: It is triggered by factors that increase body temperature, such as heat, exercise, or emotional stress, often presenting as numerous small hives. These usually first appear on the trunk and then spread distally.
- Contact urticaria: It is triggered by direct contact with an external agent.
- Aquagenic urticaria: This rare type is triggered by contact with water, regardless of its temperature.
Lookalikes
Hives can sometimes resemble other skin rashes, such as eczema, psoriasis, bug bites, contact dermatitis, and ringworm. The key features of hives, which help differentiate them from other rashes, are their transient nature and smooth surface. Additionally, they can change in shape over time.
Read more: Differences between hives and bed bug bites.
Complications
Sometimes, hives can be associated with angioedema or anaphylaxis. Angioedema is similar to hives, but the swelling occurs deeper in the skin, and it can be fatal if it affects the airways.
Anaphylaxis is a severe, life-threatening allergic reaction that can lead to swelling of the tongue, throat, and airways. Its signs and symptoms include difficulty breathing, chest tightness, coughing, abdominal cramps, vomiting, diarrhea, a fast heart rate, confusion, or dizziness
Anaphylaxis is a medical emergency and requires an epinephrine shot. If you think you are experiencing symptoms of anaphylaxis, you should go to the emergency room immediately.
Diagnosis
Diagnosing hives typically involves a combination of a physical examination, medical history analysis, and sometimes additional testing.
- Physical examination: Your doctor will examine the welts or rash on the skin, noting their appearance, distribution, and any accompanying symptoms.
- Medical history: This includes discussing any recent exposure to potential allergens, medications taken, foods eaten, and any history of allergies or similar reactions. Your doctor may also inquire about recent physical activities that could have triggered the reaction.
- Allergy testing: In cases where a specific allergen is suspected, allergy tests may be conducted. This can include skin prick tests, where small amounts of suspected allergens are introduced into the skin, or blood tests that measure the immune system’s response to certain allergens.
- Blood tests: For chronic urticaria, where the cause is not apparent, blood tests may be recommended to rule out underlying conditions like thyroid disease or autoimmune disorders.
- Diary keeping: In chronic cases, patients may be asked to keep a diary of their symptoms, diet, and activities to help identify potential triggers.
- Physical tests: If inducible urticaria is suspected, the doctor may perform tests such as the ice cube test for cold urticaria or a pressure test for pressure urticaria.
Treatment
Treatment for hives focuses on relieving symptoms and preventing future episodes. The approach can vary depending on the severity and type of hives.
Treatment of acute hives
- Cool compress: A cool compress may help in relieving the itching and calming down the inflammation.
- Antihistamines: These are the mainstay or first line of treatment for hives. They work by blocking the effects of histamine and can reduce itching and inflammation. Some examples include loratadine, cetirizine, and fexofenadine. If the patient does not respond to the standard dose within a few weeks, the dose can be increased or an additional antihistamine may be added.
- Corticosteroids: For more severe cases, or those not responding to antihistamines, oral corticosteroids may be prescribed for short-term use to reduce swelling and redness.
- Epinephrine (Adrenaline): In cases of severe allergic reactions, such as anaphylaxis, immediate treatment with an epinephrine injection is necessary.
Treatment of chronic hives
- Antihistamines: Just like acute hives, antihistamines are the mainstay or first line of treatment for chronic hives. If standard doses fail to resolve the symptoms, the dosage can be increased. An additional antihistamine may also be added.
- High-potency antihistamines: In refractory cases, a high-potency antihistamine, such as hydroxyzine, or the tricyclic antidepressant doxepin may be added.
- Corticosteroids: For severe symptoms, a short course of steroids such as oral prednisone may be added.
- Immunomodulators: In some chronic cases, where hives are resistant to standard treatments, the monoclonal antibody omalizumab (an injectable medication) or cyclosporine may be recommended.
Treatment plans are often tailored to an individual’s specific needs, so it is important to see a doctor who can help determine the most effective approach for your condition.
Prevention
It is not always possible to completely prevent hives, as in many cases the cause is unknown. However, the following measures may help prevent certain types of hives.
- Avoiding triggers: These may include dietary changes, altering medications, or avoiding certain physical stimuli.
- Stress management: Since stress can exacerbate or trigger hives, strategies like meditation, yoga, and other stress-reduction techniques can be helpful.
- Lifestyle modifications: Wearing loose-fitting clothes, using gentle skin care products, and avoiding extreme temperatures can help manage symptoms and prevent future episodes.
When to see a doctor
Although hives are generally harmless, you should seek medical attention if you have the following signs and symptoms:
- The hive lasts longer than a week.
- There is visible discharge from the bumps.
- Hives are associated with severe itching which affects your daily activities.
- You experience swelling around the eyes and lips, difficulty breathing, shortness of breath, nausea, vomiting, diarrhea, dizziness, or confusion.
Key points
Hives are raised bumps that are usually itchy but are not contagious. They often last less than 24 hours, but the chronic type can last longer.
They can be triggered by various factors, including allergens, infections, foods, stress, and other physical stimuli. Treatment is primarily symptomatic, focusing on alleviating discomfort and avoiding triggers.
References
- Schaefer P. Acute and Chronic Urticaria: Evaluation and Treatment. Am Fam Physician. 2017 Jun 1;95(11):717-724. PMID: 28671445.
- Kanani, A., Betschel, S.D. & Warrington, R. Urticaria and angioedema. Allergy Asthma Clin Immunol 14 (Suppl 2), 59 (2018).
- Godse KV. Chronic urticaria and treatment options. Indian J Dermatol. 2009;54(4):310-2. doi: 10.4103/0019-5154.57603. PMID: 20101328; PMCID: PMC2807703.
- Kayiran MA, Akdeniz N. Diagnosis and treatment of urticaria in primary care. North Clin Istanb. 2019 Feb 14;6(1):93-99. doi: 10.14744/nci.2018.75010. PMID: 31180381; PMCID: PMC6526977.
- Pozderac I, Lugović-Mihić L, Artuković M, Stipić-Marković A, Kuna M, Ferček I. Chronic inducible urticaria: classification and prominent features of physical and non-physical types. Acta Dermatovenerol Alp Pannonica Adriat. 2020 Sep;29(3):141-148. PMID: 32975301.
- Kozel MM, Mekkes JR, Bossuyt PM, Bos JD. Natural course of physical and chronic urticaria and angioedema in 220 patients. J Am Acad Dermatol. 2001 Sep;45(3):387-91. doi: 10.1067/mjd.2001.116217. PMID: 11511835.
Disclaimer: This article is for information purposes only and does not replace medical advice.