patients will develop high fever, headaches, malaise, and myalgias. Some patients will have
shaking chills and drenching sweats. Thrombocytopenia may also be noted (196). Within three
to seven days of the fever, skin eruptions of red macules, papules, and papulovesicles will
develop over the body. These lesions number between 20 and 40 and will resolve within a
week. The presence of an eschar, the lack of successive crops of vesicles over time, and the
presence of thrombocytopenia will help differentiate this entity from varicella zoster virus
infection (196).
Diagnosis can be made by comparing acute and convalescent serum antibody titers.
Indirect and direct fluorescent antibody tests using anti-R. rickettsiiantibodies have also been
reported (195). The duration of the disease can be reduced with tetracycline, but even
untreated patients typically recover without complication (195).
NODULAR RASHES
A nodule is a palpable, solid, round, or ellipsoidal lesion that may contain inflammatory cells,
organisms (fungi, mycobacterium), or cancer cells (5). Nodules usually result from disease in
the dermis.
Erythema Nodosum
Erythema nodosum is an acute inflammatory process involving the fatty-tissue layer and skin.
This condition is more common in woman. There are several causes (Table 8), including
infections with streptococci,Chlamydiaspecies, and hepatitis C (198–202).
The presentation includes fever, malaise, and arthralgias. The characteristic nodules are
painful and tender. The nodules commonly develop over the lower legs, knees, and arms (198).
Spontaneous resolution usually occurs within six weeks. Diagnosis is often clinical, but biopsy
may be needed in atypical cases.
Systemic Fungal Infections
The sudden onset of dermal nodules may indicate disseminated candidiasis. Risk factors for
disseminated candidiasis include malignancy, neutropenia, antimicrobial therapy, severe burn
Table 8 Causes of Erythema Nodosum
Infectious Noninfectious
Bacterial infections
Streptococcus pyogenes
Mycobacterium tuberculosis
Mycobacterium leprae
Cat scratch disease
Chlamydia
Enteric pathogens (Yersinia,
Campylobacter, Salmonella)
Rickettsiae
Spirochetes (syphilis)
Systemic fungal infections
Coccidioides immitis
Histoplasma capsulatum
Blastomycosis
Parasites
Amebiasis
Giardiasis
Ascaris
Viral infections
Hepatitis B
CMV
EBV
Drug reactions
Oral contraceptives
Antibiotics
Hepatitis B vaccine
Sulfonamides
Systemic disease
SLE
Ulcerative colitis
Crohn’s disease
Leukemia
Lymphoma
Sarcoidosis
Idiopathic (55%)Abbreviations: CMV, cytomegalovirus; EBV, Epstein–Barr
virus, SLE, systemic lupus erythematosus.
Source: Adapted from Ref. 193.
40 Engel et al.