Hypersensitivity (Hypersensitivity vasculitis)

Hypersensitivity vasculitis is an extreme allergic reaction

Hypersensitivity is a general term for an extreme allergic reaction to a drug or substance. The most common type of hypersensitivity, or type 1, is usually marked by a red or purple-ish rash and/or hives.

There are four types of hypersensitivity: Immediate, antibody-dependent, immune complex disease, and delayed-type.

Here's more on the characteristics of hypersensitivity, causes and examples of hypersensitivity, the types of hypersensitivity, and treatment.

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Symptoms of hypersensitivity include:

Type 1 hypersensitivity can cause anaphylaxis, which is an extreme allergic reaction that can be deadly. Symptoms of anaphylaxis include:

Hypersensitivity is caused by an extreme immune reaction to a foreign substance or illness. The most common type of hypersensitivity, or type 1, can be caused by everyday interactions with substances like pollen or pet hair. Other types of hypersensitivity can result from medications and chronic medical conditions.

The four types of hypersensitivity are:

Type 1 hypersensitivity, the most common type, is an immediate allergic reaction ranging from mild to severe. It occurs when the body releases proteins that fight against foreign substances (antibodies) in response to a substance the body is allergic (allergen).

Common allergens that can cause type 1 reactions include:

If you or a loved one experience a severe allergic reaction, please call your local emergency department immediately. Symptoms of severe immediate hypersensitivity include:

Type 2 hypersensitivity can take two to 24 hours to appear and is marked by antibodies that can destroy cells and cause tissue damage. Type 2 hypersensitivity reactions can occur during or because of:

Type 2 hypersensitivity can take days to weeks to develop. It is marked by antibodies that combine with proteins and then set into the body's tissues, which results in inflammation (the body's response to foreign invaders).

Type 3 reactions can be a part of inflammation associated with:

Type 4 hypersensitivity, the second most common type, takes at least two days to develop and is marked by skin redness. Examples include:

Treatment of hypersensitivity reactions can depend on type. The most common methods are:

Type 1 treatments include:

Type 2 treatments include:

Type 3 treatments include:

Type 4 treatments include:

Hypersensitivity refers to extreme allergic reactions to substances and drugs. The most common type of hypersensitivity, or type 1 (immediate), includes sudden allergic reactions that cause hives or rashes. Treatments for hypersensitivity can range from antihistamines and steroids for inflammation to antibiotics and epinephrine.

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By Neha KashyapNeha is a New York-based health journalist who has written for WebMD, ADDitude, HuffPost Life, and dailyRx News. Neha enjoys writing about mental health, elder care, innovative health care technologies, paying for health care, and simple measures that we all can take to work toward better health.