Browse A-Z
More <
bookmarks-menu

Rocky Mountain spotted fever

Show Alternative Names
Spotted fever

Rocky Mountain spotted fever (RMSF) is a disease caused by a type of bacteria carried by ticks.

Causes

RMSF is caused by the bacterium Rickettsia rickettsii (R Rickettsii), which is carried by ticks. The bacteria is spread to humans through a tick bite.

In the western United States, the bacteria are carried by the wood tick. In the eastern US, they are carried by the dog tick. Other ticks spread the infection in the southern US and in Central and South America.

Contrary to the name "Rocky Mountain," most recent cases have been reported in the eastern US. States include North and South Carolina, Virginia, Georgia, Tennessee, and Oklahoma. Most cases occur in the spring and summer and are found in children.

Risk factors include recent hiking or exposure to ticks in an area where the disease is known to occur. The bacteria are unlikely to be transmitted to a person by a tick that has been attached for less than 20 hours. Only about 1 in 1,000 ticks carry the bacteria. Bacteria can also infect people who crush ticks they have removed from pets with their bare fingers. Not all people will remember getting a tick bite.

Symptoms

Symptoms usually develop about 2 to 14 days after the tick bite. They may include:

  • Chills and fever
  • Confusion
  • Headache
  • Muscle pain
  • Rash -- usually starts a few days after the fever; first appears on wrists and ankles as spots that are 1 to 5 mm in diameter, then spreads to most of the body. Some infected people don't get a rash.

Other symptoms that may occur with this disease:

Exams and Tests

Your health care provider will perform a physical examination and ask about your symptoms.

Tests that may be done include:

Treatment

Treatment involves antibiotics and carefully removing the tick from the skin. To get rid of the infection, antibiotics such as doxycycline or tetracycline need to be taken. Pregnant women are usually prescribed chloramphenicol.

Outlook (Prognosis)

Treatment usually cures the infection. About 3% of people who get this disease will die.

Possible Complications

Untreated, the infection may lead to health problems such as:

  • Brain damage
  • Clotting problems
  • Heart failure
  • Kidney failure
  • Lung failure
  • Meningitis
  • Pneumonitis (lung inflammation)
  • Shock

When to Contact a Medical Professional

Contact your provider if you develop symptoms after exposure to ticks or a tick bite. The complications of untreated RMSF are often life threatening.

Prevention

When walking or hiking in tick-infested areas, tuck long pants into socks to protect the legs. Wear shoes and long-sleeved shirts. Ticks will show up on white or light colors better than on dark colors, making them easier to see and remove.

Remove ticks immediately by using tweezers, pulling carefully and steadily. Insect repellent may be helpful. Because only about 1 in 1,000 ticks carry this infection, antibiotics are not usually given after a tick bite.

Review Date: 5/19/2023

Reviewed By

Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

References

Blanton LS, Walker DH. Rickettsia rickettsii and other spotted fever group rickettsiae (Rocky Mountain spotted fever and other spotted fevers). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 186.

Bolgiano EB, Sexton J. Tickborne illnesses. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 123.

Disclaimer

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

All
Videos
Images
Rocky mountain spotted fever - lesions on arm - Illustration Thumbnail

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.)

Illustration

Deer ticks - Illustration Thumbnail

Deer ticks

Diseases are often carried by ticks, including Rocky Mountain Spotted Fever, Colorado Tick Fever, Lyme disease, and tularemia. Less common or less frequent diseases include typhus, Q-fever, relapsing fever, viral encephalitis, hemorrhagic fever, and babesiosis.

Illustration

Ticks - Illustration Thumbnail

Ticks

There are many species of ticks. Of these, a large proportion are capable of carrying disease. Diseases carried by ticks include Lyme disease, Ehrlichiosis, Rocky Mountain Spotted Fever, Colorado Tick Fever, tularemia, typhus, hemorrhagic fever, and viral encephalitis. (Image courtesy of the Centers for Disease Control and Prevention.)

Illustration

Rocky mountain spotted fever on the arm - Illustration Thumbnail

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.)

Illustration

Tick imbedded in the skin - Illustration Thumbnail

Tick imbedded in the skin

This is a close-up photograph of a tick embedded in the skin. Ticks are important because they can carry diseases such as Rocky Mountain spotted fever, tularemia, Colorado tick fever, Lyme disease, and others.

Illustration

Rocky mountain spotted fever on the foot - Illustration Thumbnail

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).

Illustration

Rocky mountain spotted fever - petechial rash - Illustration Thumbnail

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.

Illustration

Antibodies - Illustration Thumbnail

Antibodies

Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.

Illustration

 
 
Rocky mountain spotted fever - lesions on arm - Illustration Thumbnail

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.)

Illustration

Deer ticks - Illustration Thumbnail

Deer ticks

Diseases are often carried by ticks, including Rocky Mountain Spotted Fever, Colorado Tick Fever, Lyme disease, and tularemia. Less common or less frequent diseases include typhus, Q-fever, relapsing fever, viral encephalitis, hemorrhagic fever, and babesiosis.

Illustration

Ticks - Illustration Thumbnail

Ticks

There are many species of ticks. Of these, a large proportion are capable of carrying disease. Diseases carried by ticks include Lyme disease, Ehrlichiosis, Rocky Mountain Spotted Fever, Colorado Tick Fever, tularemia, typhus, hemorrhagic fever, and viral encephalitis. (Image courtesy of the Centers for Disease Control and Prevention.)

Illustration

Rocky mountain spotted fever on the arm - Illustration Thumbnail

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.)

Illustration

Tick imbedded in the skin - Illustration Thumbnail

Tick imbedded in the skin

This is a close-up photograph of a tick embedded in the skin. Ticks are important because they can carry diseases such as Rocky Mountain spotted fever, tularemia, Colorado tick fever, Lyme disease, and others.

Illustration

Rocky mountain spotted fever on the foot - Illustration Thumbnail

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).

Illustration

Rocky mountain spotted fever - petechial rash - Illustration Thumbnail

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.

Illustration

Antibodies - Illustration Thumbnail

Antibodies

Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.

Illustration

 
##RemoveMe##
 
 
 
 

 

 
 
 
© 1997-ADAM Company Logo All rights reserved.