Persistent Asymptomatic Rash
Am Fam Physician. 2020 Sep 15;102(6):369-370.
A 27-year-old soldier deployed to Afghanistan presented with a nonresolving rash on the right upper arm that developed two months earlier. The lesion initially looked like a small pimple, so the patient tried to pop it. It subsequently ulcerated and grew slowly. The rash was nonpruritic and nonpainful. It bled and scabbed over with mild trauma, such as vigorous scrubbing in the shower. The patient did not recall any insect bites or new exposures, but he had walked around camp in short sleeves. The rash did not improve with application of an antibiotic ointment. The patient had no fevers, chills, or other symptoms.
The patient's vital signs were normal. Physical examination revealed a solitary, circular, 2.4-cm, ulcerated lesion with an irregular, indurated border but no surrounding erythema (Figure 1). Physical examination findings were otherwise normal.
Based on the patient's history and physical examination findings, which one of the following is the most likely diagnosis?
A. Cutaneous leishmaniasis.
B. Cutaneous malignancy.
C. Cutaneous tuberculosis.
D. Pyoderma gangrenosum.
E. Tertiary syphilis (gumma).
The answer is A: cutaneous leishmaniasis. This patient has a typical presentation of cutaneous leishmaniasis: chronic painless lesion with a central lobular appearance and interwoven granulation tissue. The mildly indurated border is sometimes described as having a volcanic appearance.1 Leishmaniasis is a protozoal infection transmitted through a sand fly bite.2 Because the sand fly is very small, many patients do not recall being bitten.2
The spectrum of leishmaniasis ranges from isolated skin involvement to mucocutaneous and systemic involvement, depending on the causative species of Leishmania.3 Isolated cutaneous leishmaniasis usually begins as a small
Referencesshow all references
1. Dowlati Y. Cutaneous leishmaniasis: clinical aspect. Clin Dermatol. 1996;14(5):425–431....
2. Aronson N, Herwaldt BL, Libman M, et al. Diagnosis and treatment of leishmaniasis: clinical practice guidelines by the Infectious Diseases Society of America (IDSA) and the American Society of Tropical Medicine and Hygiene (ASTMH). Clin Infect Dis. 2016;63(12):e202–e264.
3. Magill A. Leishmania species. In: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Elsevier Saunders; 2015.
4. GBD 2015 Disease and Injury Incidence and Prevalence Collaborators. Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015 [published correction appears in Lancet. 2017;389(10064):e1]. Lancet. 2016;388(10053):1545–1602.
5. Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 6th ed. Elsevier; 2016.
6. Chen Q, Chen W, Hao F. Cutaneous tuberculosis: a great imitator. Clin Dermatol. 2019;37(3):192–199.
7. Al-Dwibe H, Amro A, Gashout A, et al. A pyoderma gangrenous-like cutaneous leishmaniasis in a Libyan woman with rheumatoid arthritis: a case report. BMC Res Notes. 2018;11(1):158.
This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.
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