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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 2 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 7 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 4

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 2 to 3 days (typically 7 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 6 to 8 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 1 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