Skin and Soft Tissue
575
ROCKY MOUNTAIN SPOTTED FEVER ETIOLOGY AND PATHOPHYSIOLOGY RMSF is the result of infection by Rickettsia rickettsii leading to widespread endothelial disease and diffuse injury. Multiple organs may be damaged before an adequate host response is made to this potential lethal disease. Severe coagulopathies can result leading to widespread hemostasis and DIC.
PRESENTATION AND DIAGNOSIS RMSF presents after an incubation period up to two weeks. Fever, headache, and rash are present with myalgias. Constitutional symptoms develop over time. Fever over 102oF arises and a pink macular rash presents that blanches with pressure. The rashes spread centripetally starting at the distal upper extremity and lower extremity and traveling towards the torso. Papules and petechiae form as the rash spreads and systemic symptoms begin. Jaundice and hepatosplenomegaly occur in later stages. Diagnosis is confirmed with indirect fluorescent antibody (IFA) testing.
TREATMENT RMSF requires treatment to avoid its lethal outcome. Antibiotics include doxycycline in all populations except pregnant women, who receive chloramphenicol (regardless of the risk of gray baby syndrome).
SCARLET FEVER ETIOLOGY AND PATHOPHYSIOLOGY Scarlet fever is the sequelae of GAS infection leading to widespread erythema and fever. Toxin production by GAS is implicated as the cause of this rash and disparate inflammation. 1 in 100 persons die from this ailment.
PRESENTATION AND DIAGNOSIS Scarlet fever presents following another infection caused by GAS, such as pharyngitis. Severe constitutional symptoms occur quickly and a rash appears soon thereafter. White membranes are found throughout the tongue early in the course, followed by a strawberry red tongue a few days later as the membranes fall off. Erythema becomes generalized and facial flushing is evident. Desquamation occurs after five days. Diagnosis is made clinically and confirmed with culture.
TREATMENT Scarlet fever is treated with penicillin G, cephalosporins, or erythromycin.
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