Hives, also known as urticaria, are raised, itchy, and often red welts on the skin that can vary in size and shape. They occur as a reaction to certain triggers, such as allergens, medications, insect bites, infections, or even stress.

Hives can appear anywhere on the body and may fade and reappear in different spots over a few hours or days.

The condition results from the release of histamine and other chemicals in the skin, causing swelling and irritation. While most cases resolve on their own, severe or persistent hives may require medical treatment, including antihistamines or other medications.

What Causes Hives?

Hives is caused by the following:

Allergic Reactions

Hives commonly result from allergic responses to substances like certain foods, medications, insect stings, or pollen. These allergens trigger the release of histamine, leading to the characteristic swelling and itching.

Environmental Factors

Extreme temperatures, such as heat, cold, or sudden changes in weather, can provoke hives in sensitive individuals. Prolonged exposure to sunlight, known as solar urticaria, may also cause hives in some cases.

Infections

Viral, bacterial, or fungal infections can trigger hives as part of the body’s immune response. Common culprits include respiratory infections, urinary tract infections, or strep throat.

Stress and Emotional Triggers

Stress and anxiety can lead to it in some people, as emotional distress may provoke the release of stress hormones that impact the immune system and skin.

Physical Stimuli

Pressure on the skin, such as from tight clothing or prolonged sitting, can cause a type of hives known as pressure urticaria. Similarly, scratching or rubbing the skin excessively may result in a localised reaction.

Autoimmune and Chronic Conditions

Chronic hives may be linked to autoimmune disorders, such as lupus or thyroid disease, where the immune system mistakenly attacks the body’s tissues. Other underlying health conditions, like liver disease, may also contribute.

Unknown or Idiopathic Causes

In some cases, the exact cause of hives cannot be determined. This is referred to as idiopathic urticaria and is more common in chronic hives lasting six weeks or longer.

Types of Hives

These are the types of hives that exist.

Acute Urticaria

This type of hives lasts for less than six weeks and is often triggered by allergens such as certain foods, medications, insect bites, or infections. The welts may appear suddenly and resolve once the trigger is removed or treated.

Chronic Urticaria

Chronic hives persist for six weeks or longer, with symptoms that may come and go over months or even years. The cause is often unknown (idiopathic), but they may be associated with autoimmune conditions or underlying health issues.

Physical Urticaria

Physical triggers such as pressure, heat, cold, sunlight, or vibration can cause this type of hives. Subtypes include:

• Dermatographic Urticaria: Welts appear after scratching or lightly rubbing the skin.
• Cold Urticaria: Triggered by exposure to cold temperatures or cold water.
• Heat or Cholinergic Urticaria: Caused by heat, sweating, or exercise.
• Solar Urticaria: Results from exposure to sunlight.
• Pressure Urticaria: Triggered by prolonged pressure on the skin, such as from tight clothing or sitting.

Infection-Induced Urticaria

This type occurs as a result of viral, bacterial, or fungal infections. Respiratory infections and other illnesses may provoke hives as part of the immune response.

Allergic Urticaria

This type is directly caused by exposure to specific allergens, such as foods (e.g., nuts, shellfish), medications, or insect stings. The reaction is often rapid and may be accompanied by swelling or anaphylaxis in severe cases.

Idiopathic Urticaria

In some cases, the cause of it cannot be determined, even after thorough evaluation. This is known as idiopathic urticaria and is more common in chronic cases.

Autoimmune Urticaria

This form is associated with autoimmune conditions, such as lupus or thyroid disorders. The immune system attacks the body’s own tissues, leading to persistent or recurrent hives.

Symptoms of Hives

These are the symptoms.

Raised, Itchy Welts

Hives typically appear as raised areas of skin, often red or pink, that can vary in size and shape. They are usually very itchy and may feel warm to the touch.

Changes in Size and Location

The welts can merge to form larger patches or remain small and distinct. They may appear suddenly and shift in location, disappearing in one area while appearing in another.

Swelling

In addition to the welts, it may cause swelling in deeper layers of the skin, particularly around the eyes, lips, hands, or feet. This swelling, known as angioedema, can accompany hives and may feel tender or firm.

Temporary Nature

Hives usually resolve within a few hours to a day, though new ones can continue to appear. Chronic hives, however, may persist for six weeks or longer, with symptoms recurring periodically.

Triggered or Spontaneous Onset

Symptoms may arise immediately after exposure to a trigger, such as an allergen or physical stimulus, or without any apparent cause. The intensity of the symptoms can vary from mild to severe.

Burning or Stinging Sensation

In some cases, it may be accompanied by a burning or stinging feeling, especially if they are triggered by heat, pressure, or certain irritants.

How to Treat Hives

This is how you treat hives.

Antihistamines

Over-the-counter or prescription antihistamines are commonly used to reduce itching, swelling, and redness associated with it. They work by blocking histamine, the chemical responsible for the reaction.

Avoiding Triggers

Identifying and avoiding the specific triggers, such as certain foods, medications, or environmental factors, can help prevent further outbreaks. Allergy testing may assist in pinpointing these triggers.

Cool Compresses

Applying a cool, damp cloth to the affected areas can provide relief from itching and help reduce swelling. Cool baths with soothing additives like oatmeal may also be beneficial.

Prescription Medications

In cases of severe or chronic hives, a doctor may prescribe stronger treatments, such as corticosteroids to control inflammation or biologic medications like omalizumab for chronic cases.

Lifestyle Modifications

Wearing loose-fitting, breathable clothing can minimise irritation, and avoiding hot showers or strenuous activities that cause excessive sweating may help manage symptoms. Keeping stress levels low through relaxation techniques can also reduce outbreaks.

Emergency Treatment

For severe reactions involving difficulty breathing, swelling of the throat, or other signs of anaphylaxis, immediate medical attention is required. An epinephrine injection may be necessary to reverse the reaction.

Addressing Underlying Conditions

If hives are linked to an underlying condition, such as an autoimmune disorder or chronic infection, treating the root cause can alleviate symptoms. A healthcare provider can recommend appropriate diagnostic tests and treatments.

Can Hives be Prevented?

While it may not always be possible to fully prevent hives, identifying and avoiding known triggers is the most effective way to reduce the risk of outbreaks. For those with allergies, avoiding specific allergens such as certain foods, medications, or environmental factors can help prevent hives from developing.

Wearing loose, breathable clothing, managing stress, and avoiding extreme temperatures or physical stimuli that can trigger hives are also helpful strategies. Additionally, maintaining overall skin health and taking precautions during high-risk situations, such as insect stings or exposure to chemicals, can minimise the likelihood of a reaction.

For chronic or unexplained cases, working with a healthcare provider to manage underlying conditions may help reduce the frequency and severity of it.