10 Possible Causes of Hives

One of the most common causes of hives is an allergic reaction to something you ate. The side effect can come on suddenly, even if the food is something you weren't previously allergic to. Some of the most common food allergens are nuts, dairy, and wheat.

Topical allergies occur when your body reacts negatively to something that touches your skin. Also known as contact dermatitis, this type of allergic reaction often presents as hives. Other signs of a topical allergy can include swelling, dry skin or eczema, or itching without a rash.

Occasionally, a topical allergy may require a steroid cream to treat symptoms, but they often clear up on their own.

If a person develops an allergy to prescription medication, a minor case of hives is one of the most common symptoms. Symptoms of a medication allergy usually occur within a few hours of taking the drug, though they can come on as quickly as a few minutes after applying to taking the prescription.

Individuals living with chronic stress may find themselves breaking out in hives on a semi-regular basis. This is particularly true for females with stress and anxiety disorders. Often, psychological stress, such as having an argument with a spouse or taking on too much at work, can lead to hives

Similar to contact dermatitis, vibratory urticaria occurs when the skin is irritated by direct contact with clothing or other fabrics. However, this happens most often when there's extreme friction, such as when wearing a shirt, pants, or underwear that is too tight.

Vibratory urticaria can also present with other symptoms, including swelling, redness, or itching.

Compulsive scratching or over-scratching at dry skin can lead to case of hives. This is classified as dermatographism, or hives caused by pressure or trauma to the skin.

Just because you get hives after scratching your skin, however, does not mean the scratching caused the symptom. It is also possible that something under your nails—a chemical or food residue—caused a topical allergic reaction.

Individuals who have viral or bacterial infections, including urinary tract infections, hepatitis, strep throat, or even a common cold, might find themselves with a case of hives.

This is especially true when a fever accompanies the infection. Children under 10 commonly develop this symptom when they have an infection.

Bug bites and stings are another common cause of hives, which develop when the body reacts to the venom left behind. Perhaps the best-known example is a mosquito bite.

While hives are normal after a bug bite, it's important to watch for other symptoms of an allergic reaction after being bitten. These include difficulty breathing, itching that spreads beyond the bite location, bowel problems, weakness, and severe swelling. If this occurs, it's important to seek medical care immediately.

Hives can be the result of extreme heat, either environmental or from a fever, or extreme cold. In both cases, the hives are often accompanied by lightheadedness, exhaustion, and sometimes nausea or diarrhea.

It's usually best to seek medical care when hives result after exposure to extreme temperatures, in case you have developed hypothermia or heat stroke.

While sunlight is good for most people thanks to its high levels of vitamin D, those solar urticaria or chronic acquired photosensitivity disorder may not enjoy long days in the sunshine. Solar urticaria is an allergy to sunlight that results in hives any time the skin is exposed.