A 28-year-old Hispanic man presented with a 10-month history of a pruritic rash on his right flank (Fig 1). One to two weeks prior to noticing the lesion, he had spent five days in Arizona. The lesion had doubled in size in one month, according to the patient. He had no history of similar rashes or lesions and was otherwise healthy. Self-treatment with corticosteroid creams failed.Examination revealed a 1-cm erythematous papule on his right flank, surrounded by 1-to 2-mm, nontender, nonscaly satellite papules (Fig 2). There was no lymphadenopathy or associated symptoms. What’s your diagnosis?Submit your answer, and then read the full explanation below. If you like this activity or have a suggestion, tell us about it in the comment box at the bottom of the page.
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The lesions were clinically suspected to be keloids. However, because of their atypical appearance, a skin biopsy was performed. Hematoxylin-eosin and periodic acid-Schiff stains demonstrated a granulomatous dermatitis, with the spherules of Coccidioides immitis, a dimorphic fungus that grows as a mold in soil. Coccidioides antigen fixation serologies, chest x-ray and gallium scans were normal. We diagnosed the patient with primary inoculation coccidioidomycosis.
Coccidioidomycosis, also called “Posada’s mycosis,” “Posada-Wernicke disease,” and “desert fever,” is a systemic fungal disease endemic to the southwestern United States and northern Mexico. It is usually acquired by inhaling C. immitis arthroconidia. Among people living in endemic areas 3% are infected with C. immitis annually; 60% of these cases remain asymptomatic, while 40% develop fatigue, cough, chest pain and fever.
Diagnosis is made with an antigen fixation test and imaging studies. Most patients have primary — or self-limited — disease, but about 1% progress to disseminated, disease.
Primary disease, also called “San Joaquin fever” or “valley fever,” manifests cutaneously within weeks or months after exposure as erythema multiforme, erythema nodosum or toxic erythema.
A “great imitator,” disseminated coccidioidomycosis has a wide variety of cutaneous presentations, including verrucous plaques and ulcerating or intact nodules with underlying sinus tracts.
Lesions can present as flat plaques with central atrophy. Other presentations include solitary granulomatous plaques, multiple papules, nodules or pustules. Such lesions often occur on the face. Differential diagnoses of coccidioidal skin lesions include TB, syphilis, other fungi, actinomycetes, sarcoidosis, warts and squamous cell carcinoma.
Primary cutaneous coccidioidomycosis is rare. It can manifest as chancriform lesions (i.e., painless, nontender, indurated plaques with central ulceration), papules or nodules. Its incidence is unknown. Disease is thought to develop one to three weeks after local trauma and can be followed by regional lymphadenopathy. Spontaneous recovery usually occurs after several weeks or months, and treatment is unnecessary in low-risk patients.
Diagnosis is best made with skin biopsy demonstrating fungal spherules. A KOH preparation of pus, if present, can also demonstrate fungus. As in this case, antibody tests and chest x-rays may be negative.
Progressive coccidioidomycosis, resulting either from a new infection or reactivation of an arrested primary disease, may develop months or even years after primary infections. It is more common in men than in women, except in the case of pregnant women. This may be due to the fact that the mold has estrogen-binding proteins.
The disease also occurs in association with HIV infection, immunosuppressive therapy, advanced age and certain ethnic backgrounds, including Filipino, African American, Hispanic and Asian.
Disseminated disease can be fatal if left untreated, particularly when meningitis is present. More than 70% of HIV-infected patients die within one month of diagnosis.
For patients with meningitis, treatment usually consists of amphotericin B. In less serious cases, itraconazole 200 mg twice daily or fluconazole 200-800 mg daily for six months to a year are the treatments of choice. It has not yet been determined whether either antifungal agent is more effective than more commonly prescribed agents, such as amphotericin B or ketoconazole. Primary cutaneous disease can also be treated by surgical excision.
Rather than undergo medical therapy, our patient elected to have surgical removal of the area with the papules. The pathology of the excised tissue showed scarring consistent with a resolved coccidioidomycosis infection. No spherules were observed.
Noah Scheinfeld, MD, JD, is an assistant clinical professor of dermatology at Columbia University in New York City, where he has a private practice.
Robert G. Bonillas, MD, was previously a resident in the Department of Surgery at St. Lukes-Roosevelt Hospital Center in New York City and currently lives in Scottsdale, Ariz., where he has a private practice.
1. Walsh TJ, Mitchell TG, Larone DH. “Histoplasma, blastomyces, coccidioides and other dimorphic fungi causing systemic mycoses.”In: Murray PR, Baron EJ, Pfaller MA, et al, eds. Manual of Clinical Microbiology. 6th ed. Washington, D.C.: ASM Press; 1995:751.
All online documents accessed Nov. 16, 2011.