What Causes Hives?

Your skin is like your body’s armour. It protects you from rain, sun, and everything in between. Just like armour can get dirty or show signs of wear, your skin can also change appearance as a result of external and internal factors. One of the most common things you may see on your skin are hives. 

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Hives, medically known as urticaria, are raised, itchy welts on the skin that can vary in size and appear anywhere on the body. They are a common condition resulting from various triggers that cause the release of histamine and other chemicals into the bloodstream, leading to characteristic swelling and redness. 

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But what causes these cumbersome bumps? Let’s dive into some of the possible causes of hives.

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Allergic Reactions

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One of the most common causes of hives is allergic reactions. When the immune system identifies certain substances as harmful, it releases histamine, leading to hives. Common allergens include:

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• Foods: Shellfish, nuts, eggs, and certain fruits are frequent culprits.
• Medications: Some examples include antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and certain blood pressure medications — but many more medications can also cause reactions.
• Insect Stings or Bites: Reactions to bee stings, mosquito bites, or other insect interactions can result in hives.

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Physical Triggers

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Certain physical factors can induce hives, including:

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• Temperature Extremes: Exposure to cold (cold urticaria) or heat can lead to hives. Cold-induced hives appear shortly after exposure to cold air or water. 
• Sunlight: Some individuals develop hives due to sun exposure, a condition known as solar urticaria.
• Pressure: Tight clothing or prolonged pressure on the skin can cause pressure-induced hives.
• Exercise: Physical activity can trigger cholinergic urticaria, characterized by small hives surrounded by areas of redness. 

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Underlying Health Conditions

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Chronic hives, lasting more than six weeks, can be associated with underlying health issues:

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• Autoimmune Disorders: Conditions like thyroid disease, lupus, or rheumatoid arthritis can cause the immune system to attack healthy tissues, leading to hives.
• Infections: Bacterial or viral infections, such as hepatitis or sinusitis, have been linked to hives.
• Vasculitis: Inflammation of blood vessels, known as urticarial vasculitis, can present with hives that are often painful and last longer than typical hives. 

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Idiopathic Causes and Other Potential Triggers

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In many cases, especially with chronic hives, no identifiable cause is found. This condition is termed chronic idiopathic urticaria. Despite extensive testing, the exact trigger remains unknown in these instances. 

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Additional factors that may cause hives include:

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• Stress: Emotional stress can exacerbate hives in some individuals.
• Hormonal Changes: Fluctuations in hormones, such as during pregnancy or menopause, can trigger hives.
• Dietary Additives: Certain food additives and preservatives may lead to hives in sensitive individuals.

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Understanding the diverse causes of hives is crucial for effective management. Identifying and avoiding known triggers, seeking appropriate medical evaluation for underlying conditions, and implementing suitable treatment strategies can significantly improve your skin’s health!

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The information on this site is for informational purposes only and should not replace direct medical advice, diagnosis, or treatment from your doctor or another qualified healthcare provider.

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Sources: 

“Hives and angioedema.” Mayo Clinic.

“Hives.” Cleveland Clinic.