It's not a drug reaction but a fungal infection in an immunosuppressed patient (tinea corporis)

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology

A 37-year-old Caucasian male with severe asthma and allergic rhinitis. He was initially placed on omalizumab but developed an anaphylactic reaction and his treatment regimen was changed to cyclosporin. He was not able to tolerate cyclosporin and has been on methotrexate for six weeks. He felt much better after switching to methotrexate. His shortness of breath improved and he was able to exercise again.

However, within a week of starting methotrexate, he noted tiny skin lesions of on his both feet. He did not pay any attention until about a week earlier when he started to notice that the lesions on his feet had expanded. They itch and he also noticed new lesions located on the left thigh and knee area, and on his left forearm.

Past medical history (PMH)

Asthma, allergic rhinitis.


Pulmicort three puffs b.i.d., Combivent prn, Zyflo 1200 mg po b.i.d., Prevacid 20 mg po b.i.d., Flonase two sprays in each nostril b.i.d., prednisone 7.5 mg po every other day. Methotrexate 15 mg every week on Thursdays.

Physical examination

Temperature 97.9, heart rate 86, respiratory rate 14, blood pressure 122/78.
Skin: He has multiple erythematous plagues which affect both feet up to the size of 2 x 3 cm with central clearing and advancing edge. He also has fungal lesions between his toes. No clear fungal infection of his nails. He also has 7 cm ringworm lesion on the inner aspect of his left knee with central clearing and a blanching edge. He has 3 cm ringworm lesion on his left forearm with central clearing and advancing edge.
Eyes: Normal. Ears: Cerumen, otherwise normal. Nose: Pale boggy turbinates on both sides. Throat: Normal.
Respiratory system clear to auscultation bilaterally.
Cardiovascular system: Clear S1, S2.
Abdomen: Soft, non-tender, non-distended. Extremities: No edema.

Ringworm on the arm, tinea corporis due to Trichophyton mentagrophytes. Image source: Wikipedia, CDC/Dr. Lucille K. Georg, public domain.

What is the most likely diagnosis?

Tinea corporis (ringworm) in an immunosupressed patient with severe asthma who is treated with prednisone and methotrexate.

What treatment would you recommend for this patient?

His liver function tests were normal a few weeks ago. He was prescribed Terbinafine (Lamisil) 250 mg po daily for two weeks. He is to return to our clinic in 3 weeks.

If a patient has a fungal infection of the toenails, the duration of Terbinafine (Lamisil) is 12 weeks as opposed to 2 weeks in our case.

Final diagnosis

Tinea corporis (ringworm) in an immunosupressed patient.


Topical Treatment of Common Superficial Tinea Infections. AFP, 2002.
Diagnosis and Management of Common Tinea Infections. AFP, 1998.
Tinea Corporis. eMedicine Specialties, 2008.

Published: 02/26/2009
Updated: 02/26/2009

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