From the Guidelines
Mediterranean spotted fever should be diagnosed and treated promptly with doxycycline, without waiting for laboratory confirmation, due to its potential severity and high mortality rate, as evidenced by a case-fatality rate of 21% among hospitalized adults in Portugal 1. The diagnostic criteria for Mediterranean spotted fever include:
- Fever, headache, myalgia
- A characteristic black eschar (tache noire) at the tick bite site
- A maculopapular or petechial rash that typically appears 3-5 days after fever onset, often involving palms and soles Laboratory confirmation involves:
- Serology (IFA or ELISA)
- PCR of blood or tissue samples
- Immunohistochemical detection of Rickettsia conorii in skin biopsies The treatment options for Mediterranean spotted fever are:
- Doxycycline at 100 mg twice daily for adults and 2.2 mg/kg twice daily for children (regardless of age) for 7-14 days
- Alternative treatments include chloramphenicol (50-75 mg/kg/day divided in four doses) for pregnant women in the first trimester, or fluoroquinolones like ciprofloxacin (500 mg twice daily) or macrolides like azithromycin (500 mg on day 1, then 250 mg daily) for patients with contraindications to doxycycline, as recommended by the CDC 1. It is essential to note that delayed therapy is associated with increased mortality, particularly in elderly patients and those with comorbidities, highlighting the importance of prompt treatment 1. Some key points to consider in the diagnosis and treatment of Mediterranean spotted fever include:
- The disease is endemic in the Mediterranean basin, Middle East, parts of Africa, and the Indian subcontinent 1
- The principal tick vector in Europe, Israel, and North Africa is Rh. sanguineus 1
- Dogs can serve as reservoir hosts for R. conorii, and infected Rh. sanguineus ticks can transfer from dogs to humans during interactions 1
- The mean incubation period is 6 days (range: 1–16 days) after being bitten by an infected tick 1
From the Research
Diagnostic Criteria for Mediterranean Spotted Fever
- The disease is characterized by fever, maculo-papular rash, and a black eschar at the site of the tick bite ('tache noir') 2
- Clinical presentation may include high fever, headache, nausea, weakness, and generalized maculopapular rash 3
- Laboratory diagnosis can be confirmed by Rickettsia conorii serology using indirect immunofluorescence assay method 3
- In some cases, the symptomatology of hemorrhagic fever associated with Rickettsia conorii may be confused with that of sepsis in clinical practice 3
Treatment Options for Mediterranean Spotted Fever
- Doxycycline is a commonly used treatment, with a dosage of 200 mg/day for 7 days 3
- Azithromycin is also used, especially in children, with no reported cases of therapeutic failure or side-effects 4
- Clarithromycin is a good alternative to doxycycline or josamycin in the treatment of MSF, with no adverse reactions to treatment or relapses reported 5
- Treatment should be started as soon as possible, and monitoring of heart function is recommended, even in the absence of underlying risk factors, due to the potential for cardiac complications such as atrial fibrillation 2 or coronary involvement 6
Special Considerations
- Children are a particularly vulnerable group due to their close contact with household animals and frequent outdoor play 4
- In endemic regions, the incidence of Mediterranean spotted fever may be higher, and fever, myalgia, abdominal pain, and headache are common presenting symptoms 4
- Exanthema is a predominant cutaneous finding, and eschars are found in a significant proportion of patients 4