Case series: Tinea incognito

Introduction: Patient 1: 24 year old female presented with widespread pustular eruption involving trunk and limbs and feeling unwell since one week. Recently treated for biopsy-proven guttate psoriasis of limbs with topical corticosteroids, narrow band UVB (UVB) and Penicillin for heavy growth of Staphylococcus aureus on lesions. Patient 2: 79 year old male with history of Mycosis fungoides (MF) presented with two weeks of worsening erythroderma with widespread deep erythema and scaling affecting whole body with relative sparing of face and palms. MF previously treated with topical corticosteroids, UVB and Methotrexate. Recent tests showed no progression of MF.
Investigations: Patient 1's biopsies revealed only sub-corneal pustule and sub-epidermal vesicle with neutrophils. Skin scrapings later positive for Microsporum canis (zoophilic fungus). Biopsies were then reviewed and follicular fungal hyphae found. History re-visited and recent contact with kitten with rash. Patient 2's biopsy showed residual features of MF. Skin scrapings then demonstrated surface postulation and hyphae which was later confirmed as Tricophyton rubrum.
Management: Both patients improved with anti-fungal treatment with topical Terbinafine 1% cream daily and oral Terbinafine for Patient 2.
Discussion: These cases represent two isolated cases of tinea incognito severe enough to warrant hospital admission. They demonstrate the difficulty of biopsy-proven diagnosis where little to no fungal elements seen and that biopsies may require re-analysis in light of new evidence. Both cases relied on fungal scrapings which may yield inadequate sample if little scaling due to recent steroid cream application or which may be delayed where diagnosis not suspected.

Dr. Kylie Beem

Greenslopes Private Hospital

Dr Kylie Beem is a senior house officer at Greenslopes Private Hospital in Brisbane who is seeking to specialize in dermatology. Kylie has completed several dermatology terms at the Princess Alexandra Hospital in Brisbane as well as volunteering her time at the Mater Hospital dermatology outpatient clinics. She has also completed elective terms with private dermatology practices and spent time volunteering as a medical student in the Solomon Islands dealing with a wide variety of tropical skin diseases. She is passionate about dermatology and has also contributed to running the Australasian College of Dermatologists' Fellowship clinical examinations held in Brisbane in 2016. She is a member of the Brisbane Hospitals Dermatology Group.