FIGURE 66.9 Rocky Mountain spotted fever The rash starts on the wrists and ankles and spreads centripetally (Courtesy of Sidney Sussman In: Arndt KA, Hsu JT, Alam M, et al., eds Manual of Dermatologic Therapeutics 8th ed Philadelphia, PA: Wolters Kluwer; 2014 With permission.) The rash of RMSF begins on the third or fourth day of a febrile illness as a macular or papular eruption on the extremities, most commonly the wrists and ankles ( Fig 66.9 ) Over the next days, the rash spreads typically to the palms and soles as well as centrally to involve the back, chest, and abdomen but still have an acral-predominant (arms, legs, palms, soles) distribution Initially, the lesions are erythematous macules that then become more confluent and purpuric and can be papular The severity of the rash is proportional to the severity of the disease All patients with RMSF have some degree of vasculitis that is the basis for many of the associated systemic symptoms The patients are usually toxic appearing Systemic signs and symptoms include fever, headache, myalgia, conjunctivitis, vomiting, seizures, myocarditis, heart failure, shock; periorbital, facial, or peripheral edema; and disseminated intravascular coagulation or purpura fulminans Most commonly, the diagnosis is based on clinical presentation with a history of potential tick exposure The causative organism is not routinely cultured because of the danger to laboratory personnel Diagnosis is best made by a serologic test such as indirect immunofluorescence antibody (IFA) assay Antibodies can be detected to 10 days after onset of illness Some reference laboratories are now offering polymerase chain reaction (PCR) testing Thrombocytopenia, hyponatremia, and increased serum aminotransferase levels can develop as the disease progresses Doxycycline is the drug of choice for therapy in patients of all ages (despite its risk for potentially staining developing teeth) at a dose of mg/kg/day in two divided doses (maximum of 100 mg bid), intravenously or orally Chloramphenicol is a less optimal alternative and is not effective against ehrlichiosis, which can present similarly to RMSF Therapy is continued until the patient is afebrile for at least to days (typically to 10 days of antibiotic therapy) Secondary Syphilis (See also Chapters 88 Dermatologic Urgencies and Emergencies and 94 Infectious Disease Emergencies ) Secondary syphilis is a widespread eruption that occurs due to dissemination of untreated primary syphilis Manifestations of secondary syphilis usually occur to weeks after the appearance of the primary lesion, which is typically painless and so may have gone unnoticed The rash of secondary syphilis is characterized by a generalized cutaneous eruption, usually composed of brownish, dull-red macules or papules that range in size from a few millimeters to cm in diameter They are generally discrete and symmetrically distributed, particularly over the trunk, where they follow the lines of cleavage in a pattern similar to pityriasis rosea Secondary syphilis can be distinguished from pityriasis rosea by papular lesions on the palms ( Fig 66.10 ) and soles, and the presence of systemic symptoms, such as general malaise, fever, headaches, sore throat, rhinorrhea, lacrimation, and generalized lymphadenopathy The exanthem extends rapidly and is usually pronounced and may be short-lived or last months One needs a high level of suspicion when viewing rashes in sexually active (or sexually abused) children to make the diagnosis of secondary syphilis Acquired syphilis is sexually contracted from direct contact with ulcerative lesions of the skin or mucous membranes of an infected individual Diagnosis may be presumed after a positive nontreponemal test, such as the VDRL slide test, rapid plasma reagin test, or automated reagin test Diagnosis should be confirmed by a treponemal test, such as the fluorescent treponemal antibody absorption test, the microhemagglutination test for Treponema pallidum, or the T pallidum immobilization test Penicillin is the treatment of choice unless contraindicated, in which case tetracycline, doxycycline, ceftriaxone, or erythromycin may be substituted Length of therapy should be based on duration and stage of infection Concomitant sexually transmitted diseases should be sought and treated empirically HIV testing is recommended for patients with secondary syphilis FIGURE 66.10 Secondary syphilis (Reprinted with permission from Stedman’s Medical Dictionary for the Health Professions and Nursing, Illustrated (Standard Edition) 6th ed Philadelphia, PA: Lippincott Williams & Wilkins; 2007.) FUNGAL INFECTIONS Cutaneous fungal infections can be divided into a few clinical categories: dermatophytes, yeasts, deep fungal infections with cutaneous manifestations, and opportunistic fungal infections Dermatophytes Dermatophytes are fungi that have a tropism for infecting skin, hair, and nails The most common types are Trichophyton species, Microsporum, and Epidermophyton species The specific types of infection are named for their body site of involvement because they can present differently based on location Tinea corporis presents with scaling patches that have a raised border (annular) ( Fig 66.11 ) Occasionally the fungi and resultant inflammation can cause blistering (bullous tinea) Tinea pedis can present with scaling