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Severe Allergies With a Rash and Headache

author image James Holloway
Dr James Holloway has been writing about games, geek culture and whisky since 1995. A former editor of "Archaeological Review from Cambridge," he has also written for Fortean Times, Fantasy Flight Games and The Unspeakable Oath. A graduate of Cambridge University, Holloway runs the blog Gonzo History Gaming.
Severe Allergies With a Rash and Headache
Allergies to substances such as cat dander or pollen can cause headaches. Photo Credit Polka Dot Images/Polka Dot/Getty Images

When rashes and headaches appear suddenly, one likely cause is an allergic reaction. Allergies can cause rashes and headaches ranging from minor irritation to painful and frightening attacks. A wide variety of allergies can cause these types of reaction. As a result, sufferers should always consult a doctor to determine the cause of the rashes and headaches and what further treatment is required. Many rashes and headaches caused by allergies respond well to simple treatments. A visit to your doctor will help you determine how to treat your allergies.


An allergic reaction occurs when the body's immune system overreacts to the presence of a harmless substance, such as pollen or animal dander. This substance is called an "allergen." When the body detects the presence of an allergen, it releases a chemical called "histamine." As the histamine levels in the bloodstream rise, a number of symptoms appear as the body tries to flush the allergen out and prevent it from re-entering. These symptoms can manifest in different ways.


Allergic reactions can produce various different kinds of rash. Hives are raised welts which appear after exposure. They are commonly produced by food allergies, which can also result in redness, itching and swelling around the mouth. Other forms of allergy, such as latex allergies, can produce a rash called "dermatitis" which appears following skin contact with the allergen. Allergic rashes can vary in intensity. Severe allergies can lead to prolonged and intense rashes. Delayed reactions are often more severe.


"Allergic rhinitis" is the name for a group of symptoms that commonly occurs in people who suffer from allergies to pollen, cat dander and other nasal irritants. Early symptoms can include a runny nose and watering, irritated eyes. Nasal congestion develops later, leading to congestion headaches. Sufferers may experience an uncomfortable pressure in the upper nasal region. Severe allergic rhinitis can also lead to disorientation and impaired memory. Allergic rhinitis and dermatitis can occur together in many cases, including as a response to some types of food allergy.


Headaches and rashes resulting from allergies can be treated in a number of ways. Antihistamines reduce the level of histamine in the blood, reducing the cause of the reaction. Additionally, nasal congestion and resulting headaches can be treated with decongestants and painkillers, while topical creams reduce the swelling and itching of rashes. Allergies themselves cannot be effectively treated, although they do sometimes diminish with time; sufferers should therefore take care to avoid the allergens that provoke rashes and headaches. Always work with your doctor to treat your allergies.

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