Rocky Mountain spotted fever

Empirical Administration of Doxycycline for Rocky Mountain Spotted Fever: A Case Report

Rocky Mountain spotted fever (RMSF) is a tick-borne illness that can cause extreme sickness, even death, in otherwise healthy individuals. Sometimes, it is difficult to confirm the diagnosis as the rash often lags behind other symptoms of the illness and may not occur at all. Other symptoms of RMSF are nonspecific, such as fever, headache, and malaise. Besides the confirmatory serology test, antibody titers remain negative in the early phase of the illness. Here, we reported a case of a 21-year-old male who presented with fever, mild headache, body aches, joint pain, dry cough, and characteristic maculopapular rash after visiting a tick-prone area. Doxycycline was started because symptoms and laboratory values heightened our suspicion for the diagnosis of RMSF. His condition improved gradually, and his labs became normal. Our study supports the empirical use of doxycycline in suspected RMSF cases.

Atypical Rocky Mountain spotted fever with polyarticular arthritis

BACKGROUND

Rocky Mountain spotted fever (RMSF) is an acute, serious tick borne illness caused by Rickettsia rickettsi. Frequently, RMSF is manifested by headache, a typical rash and fever but atypical disease is common, making diagnosis difficult. Inflammatory arthritis as a manifestation is rare. The purpose of this study is to describe a patient with serologically proven RMSF who presented in an atypical manner with inflammatory arthritis of the small joints of the hands and to review the previously reported patients with rickettsial infection and inflammatory arthritis.

METHODS

An 18-year-old woman presented with a rash that began on the distal extremities and spread centrally, along with hand pain and swelling. She had tenderness and swelling of the metacarpophlangeal joints on examination in addition to an erythematosus macular rash and occasional fever.

RESULTS

Acute and convalescent serology demonstrated R rickettsi infection. She was successfully treated with doxycycline.

CONCLUSIONS

Inflammatory arthritis is a rare manifestation of RMSF or other rickettsial infection with 8 previously reported patients, only 1 of whom had RMSF. Physician must have a high index of suspicion for RMSF because of atypical presentations.

Dose-response model of Rocky Mountain spotted fever (RMSF) for human

Rickettsia rickettsii is the causative agent of Rocky Mountain spotted fever (RMSF) and is the prototype bacterium in the spotted fever group of rickettsiae, which is found in North, Central, and South America. The bacterium is gram negative and an obligate intracellular pathogen. The disease is transmitted to humans and vertebrate host through tick bites; however, some cases of aerosol transmission also have been reported. The disease can be difficult to diagnose in the early stages, and without prompt and appropriate treatment, it can be fatal. This article develops dose-response models of different routes of exposure for RMSF in primates and humans. The beta-Poisson model provided the best fit to the dose-response data of aerosol-exposed rhesus monkeys, and intradermally inoculated humans (morbidity as end point of response). The average 50% infectious dose among (ID₅₀) exposed human population, N₅₀, is 23 organisms with 95% confidence limits of 1 to 89 organisms. Similarly, ID₁₀ and ID₂₀ are 2.2 and 5.0, respectively. Moreover, the data of aerosol-exposed rhesus monkeys and intradermally inoculated humans could be pooled. This indicates that the dose-response models fitted to different data sets are not significantly different and can be described by the same relationship.

Diagnosis and treatment of tick infestation and tick-borne diseases with cutaneous manifestations

Hard and soft ticks may be associated directly or indirectly with a number of dermatoses, both infectious and inflammatory in origin. Morbidity may occur as a result of tick bites, tick toxicosis, and even infestation. These arthropod vectors may transmit life-threatening protozoan, bacterial, rickettsial, and viral diseases with systemic and cutaneous findings. Additionally, ticks may transmit more than one pathogen with subsequent human coinfection. This article reviews the presentation of tick-borne illnesses and the medical management of these diseases. Among others, diseases such as ehrlichiosis, anaplasmosis, babesiosis, tularemia, borrelioses, tick-borne encephalitides, rickettsial spotted fevers, and tick typhus are discussed in this article. The recognition of skin manifestations associated with these diseases is paramount to early diagnosis and treatment initiation.

Rocky Mountain spotted fever

Rocky Mountain spotted fever (RMSF) is a life-threatening disease caused by Rickettsia rickettsii, an obligately intracellular bacterium that is spread to human beings by ticks. More than a century after its first clinical description, this disease is still among the most virulent human infections identified, being potentially fatal even in previously healthy young people. The diagnosis of RMSF is based on the patient's history and a physical examination, and often presents a dilemma for clinicians because of the non-specific presentation of the disease in its early course. Early empirical treatment is essential to prevent severe complications or a fatal outcome, and treatment should be initiated even in unconfirmed cases. Because there is no vaccine available against RMSF, avoidance of tick-infested areas is still the best way to prevent the infection.

Rocky Mountain spotted fever

Rocky Mountain spotted fever (RMSF) is an unusual but important dermatological condition to identify without hesitation. The classic triad of headache, fever, and a rash that begins on the extremities and travels proximally to involve the trunk is found in a majority of patients. The cutaneous centripetal pattern is a result of cell to cell migration by the causative organism Rickettsia rickettsii. Such individuals should receive prompt antimicrobial therapy and supportive care to avoid serious and potentially fatal complications.

Dermatoses from ticks

Ticks are ectoparasites that cause dermatologic disease directly by their bite and indirectly as vectors of bacterial, rickettsial, protozoal, and viral diseases. In North America, where ticks are the leading cause of vector-borne infection, dermatologists should recognize several tick species. Basic tick biology and identification will be reviewed. Tick bites cause a variety of acute and chronic skin lesions. The tick-borne diseases include Lyme disease, tick-borne relapsing fever, tularemia, babesiosis, Rocky Mountain spotted fever, other spotted fevers, ehrlichiosis, Colorado tick fever, and others. The epidemiology, clinical features, diagnosis, and treatment of these diseases are reviewed with an emphasis on cutaneous manifestations. Finally, the prevention of diseases caused by ticks is reviewed.