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Fever

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Elevated temperature

Hyperthermia

Pyrexia

Febrile

Fever is the temporary increase in the body's temperature in response to a disease or illness. A child has a fever when the temperature is at or above one of these levels:100. 4°F (38°C) measured in the bottom (rectally)99. 5°F (37. 5°C) measured in the mouth (orally)99°F (37. 2°C) measured under the arm (axillary)An adult probably has a fever...

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Self Care

When your baby or infant has a fever

The Basics

A Closer Look

Fever of unknown origin (Alternative Medicine)

Fever blister

A fever blister is a sore from an infection caused by the herpes simplex virus, characterized by an eruption of small and usually painful blisters on the skin of the lips, mouth, gums, or the skin around the mouth. A fever blister is highly contagious. A canker sore is a benign, open sore in the mouth, which appears as a painful white or yellow sore (ulcer) surrounded by a bright red area, which is not contagious. A fever blister is very different from a canker sore, although they both develop in close proximity in area of the mouth.

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Rocky mountain spotted fever - lesions on arm

This is the appearance of the rash of Rocky Mountain Spotted Fever on the hands and forearms. The rash starts on the hands and feet and later spreads to the trunk. It is caused by a bacteria transmitted to humans by a tick bite. (Image courtesy of the Centers for Disease Control and Prevention. )

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Rocky mountain spotted fever on the arm

Rocky Mountain Spotted Fever is a disease transmitted to humans by a tick bite. The spots begin as flat (macular) red (erythematous) patches that may bleed into the skin, causing purplish spots (purpura). The disease is named after its characteristic spots. (Image courtesy of the Centers for Disease Control and Prevention. )

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Rocky mountain spotted fever on the foot

Rocky Mountain spotted fever is caused by the organism Rickettsia rickettsii and is transmitted by a tick bite. It is a serious infection that produces a classical rash in about 90% of infected individuals. This is the typical appearance of the rash. There are many symptoms that affect the entire body (systemic).

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Rocky Mountain spotted fever - petechial rash

Rocky Mountain spotted fever is a potentially fatal infection transmitted to humans by ticks. This photograph shows the classical appearing rash which often begins on the wrists and ankles, and spreads rapidly towards the center of the body. The rash may also be present on the palms and soles.

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Signs of scarlet fever

Scarlet fever is a disease caused by an infection with group A beta-hemolytic streptococcal bacteria that occurs in a small percentage of people with strep throat. The illness typically begins with a fever and sore throat. It may be accompanied by chills, vomiting, abdominal pain and malaise. The streptococcal bacteria produces a toxin that causes a rash that appears one to two days after the onset of illness. The rash initially appears on the neck and chest, then spreads over the body. While the rash is still red, the patient may develop Pastia's lines, bright red coloration of the creases under the arm and in the groin.

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Dengue fever

Dengue fever, or West Nile fever, is a mild viral illness transmitted by mosquitoes which causes fever, rashes and muscle and joint aches. Treatment includes rehydration and recovery is expected. A second exposure to the virus can result in Dengue hemorrhagic fever, a life-threatening illness.

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Review Date: 7/3/2022+

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