Rocky Mountain Spotted Fever

Rocky Mountain spotted fever is a life-threatening tickborne bacterial infection that is transmitted to humans through a tick bite. The bacterium responsible for transmission is bacterium Rickettsia rickettsii. Although Rocky Mountain spotted fever can be potentially fatal, it is curable disease.

Despite the name, the disease is not just limited to Rocky Mountain and can occur at any places. This disease is usually common during summer months and on the areas where ticks are most active. The organism is transmitted through the body via blood and the lymphatic system.

Rocky Mountain spotted fever Symptoms

The initial symptoms usually develop within 2 to 14 days after the tick bite. As most tick bites are painless one may not remember the tick bite. The disease usually begins with flu-like symptoms with several other symptoms listed below:

• Chills
• Fever
• Headache
• Muscle pain
• Abdominal pain
• Lack of appetite
• Nausea and vomiting

RMSF can be very fatal if not treated quickly within first few days of symptoms, so be sure to contact your health care provider if you have above symptoms.

Skin Rash in RMSF

Rash may be seen 2-6 days after the onset of fever. However around 10% of the patients may never develop rash. The rash usually begins as erythematous maculopapular eruption on the wrists and ankles and spreads on both direction down to the palms and soles, as well extend upward to legs and arms to involve the trunk. The involvement of palm and soles may occur late after 5-6 days or may never develop in some patients. Facial rash is usually not seen and involvement of rash on scrotum and vulva help more in accurate diagnosis.

Rocky Mountain Spotted Fever

Rocky Mountain Spotted Fever

Rocky Mountain Spotted Fever

Early in the course of disease the rash may be blanching, macular, and non-itchy. If not treated, over few days the rash becomes petechial, this is a sign of progression to severe disease and in rare cases necrosis of skin and gangrene may occur which is usually fatal requiring amputation of the affected area. In individual with dark skin, rash may be difficult to see in early stages. Other cutaneous manifestations include mucosal ulcers, postinflammatory hyperpigmentation, and jaundice.

Other Systemic Involvements

Infection of Conjunctiva may be seen in around 30-35% of the patients. Periorbital swelling may also be seen, especially in children. Swelling of the dorsal part of hands and foot may be present. Other involvements are listed as below:

• Myocarditis
• Cough and pneumonia
• Hepatomegaly and splenomegaly
• Jaundice
• Diarrhea
• Acute renal failure
• Various neurological manifestations like: photophobia, meningismus, amnesia, other bizarre behaviour suggestive of psychiatric illness, hearing loss, vertigo

What tests will your doctor perform?

Your doctor may perform several tests to confirm the diagnosis and to exclude other possible diseases, the tests include the following.

• Complete blood count
• Kidney and liver function tests
• Urinalysis for checking protein and blood in urine
• Prothrombin time (PT)
• Partial thromboplastin time (PPT)
• Skin Biopsy
• Antibody titer

Rocky Mountain spotted fever Treatment

As delay in treatment can be very fatal, early treatment with antibiotics is very important, there is no time waiting for any test results to come out.

Doxycycline is considered as the first line treatment for both children and adults, and is most effective if started before the fifth day of symptoms. Doxycycline is usually contraindicated in early pregnancy due to its involvement in fetal teeth and bone development and hepatotoxicity. In such cases, your doctor may prescribe you with chloramphenicol. Many people have concern that doxycycline and tetracycline may stain the teeth of children. However, research have shown that short courses of doxycycline to treat RMSF do not cause significant dental staining. [1]

Complications and prognosis

Rocky Mountain spotted fever is usually curable without any complications if treated early. If left untreated or delayed in treatment may lead to complications like paralysis, hearing loss, and nerve damage, renal failure and many others or even death ( 3%).

Prevention Tips

Better avoid hiking or walking in tick-infested places, if you do go, always wear long sleeves shirts and protect your legs and hands with socks and gloves. If you see any ticks, remove it immediately with tweezers or any other comfortable instruments. Several insect repellents are available in market, use them. Insect repellent may be helpful. Not all ticks carry this infection (less than 1% carry), but it is better to prevent early than regret later.

References:
[1] Lochary ME, Lockhart PB, Williams WT Jr. Doxycycline and staining of permanent teeth. Pediatr Infect Dis J. May 1998;17(5):429-31.
[2] Minniear TD, Buckingham SC. Managing Rocky Mountain spotted fever. Expert Rev Anti Infect Ther. Nov 2009;7(9):1131-7.