FIGURE 66.7 Erysipeloid (Reprinted with permission from Betts RF, Chapman SW, Penn RL Reese and Betts’ a Practical Approach to Infectious Diseases 5th ed Philadelphia, PA: Lippincott Williams & Wilkins; 2002.) Culture of the affected skin can yield the pathogen but caution is needed in interpreting these results as cultures will not differentiate colonization from true infection Therapy with topical mupirocin or bacitracin is often effective for bacterial intertrigo but systemic antibiotics such as cephalexin or clindamycin can be used in more extensive cases Other Pathogens Rocky Mountain Spotted Fever Rocky Mountain spotted fever (RMSF), one of the most virulent infections identified in humans, is caused by Rickettsia rickettsii transmitted by the bite of a tick (see Chapters 88 Dermatologic Urgencies and Emergencies and 94 Infectious Disease Emergencies ) Confirmed cases have been reported from all parts of the United States from varying tick vectors RMSF is associated with a fatality rate of 5% with antimicrobial treatment