An Unusual Presentation of Cutaneous Alternariosis with Bullous Lesions in A Patient with Diabetes Mellitus

Diabetes mellitus considered to represent an immunodecient state signicantly predisposes patients to all types of opportunistic invasive fungal infection. However, very few cases of cutaneous alternariosis associated with diabetes have been reported previously. Herein, we describe a rare case of cutaneous alternariosis in an elderly diabetic patient with antecedent local trauma.


Abstract
Diabetes mellitus considered to represent an immunode cient state signi cantly predisposes patients to all types of opportunistic invasive fungal infection. However, very few cases of cutaneous alternariosis associated with diabetes have been reported previously. Herein, we describe a rare case of cutaneous alternariosis in an elderly diabetic patient with antecedent local trauma.

Main Tex
An 82-year-old man presented with erythematous and blistering rashes on his upper extremities for 1 month. He was treated with antibacterial agents and incision and drainage of blisters with little improvementin local hospital. The lesions extendedwith development of scattered pustules over time.He recalled a history of prior abrasion on the forearms by accident tumble. His medical history was remarkable for diabetes mellitus controlled with diet and exercise. On examination, widespread erythematous, slightly in ltrated plaques and tense blisters, intermingled with pustules, sometimes eroded and crusting were noted over the dorsum of both hands, forearms, and part of the upper arms ( Fig. 1 A, B, C, D). Laboratory ndings disclosed an elevated white blood cell count of 18. 87×10 9 /Lwith 81.87% neutrophils and C-reactive proteinof 17.0 mg/dL.Chest X-ray and other hematological investigations including HIV serology were normal or negative.Direct microscopy of exudate staining with calco uor white showed spores and septate hyphae ( Fig.1 E). A skin biopsy demonstrated dermal edema and granulomatous in ltrate with multiple rounded to oval, thick-walled spores highlighted by the periodic acid-Schiff and methenamine silver staining (Fig. 1 F, G, H). Fungal culture of both exudate and tissue yielded Alternaria species characterized by colonies with gray-white and cottony surface after 4 days of incubation ( Fig. 1 I). Slide culture revealed brown septate hyphae and multiple darkly pigmented ovoidal conidia muriformes in groups and branched chains ( Fig. 1 J). The pathogen was identi ed as Alternaria alternata by internal transcribed spacer region nucleotide sequencing. A diagnosis of cutaneous alternariosis was made.He was treated with itraconazole 200 mg twice daily and the lesions resolved completely after 2 months.
Cutaneous alternariosis is a phaeohyphomycosis caused by Alternaria species and occurs predominantly in immunocompromised hosts. Local trauma facilitates the penetration of the pathogen. Diabetes mellitus considered to represent an immunode cient state signi cantly predisposes patients to all types of opportunistic invasive fungal infection. However, very few cases of cutaneous alternariosis associated with diabetes have been reported previously. Herein, we describe a rare case of cutaneous alternariosis in an elderly diabetic patient with antecedent local trauma.
The spectrum of clinical presentations is broad. Lesions can appear as either single or multiple, reddishbrown papulonodular, pustular, ulcerated or crusted plaques. To our knowledge, there are no prior reports of cutaneous alternariosis presenting with bullous lesions. Alternaria can be isolated from normal human skin or as a laboratory contaminant, therefore, histological con rmation is important to establish the clinical signi cance of a positive culture. In our patient, fungal elements were detected in both exudate and the biopsy specimens. Subsequently Alternaria alternata was identi ed by mycological culture and molecular identi cation.
Management of cutaneous Alternaria infection includes antifungal therapy, surgery, and control of underlying conditions. Itraconazole has become the most common therapy and generally has favorable outcomes.
In conclusion, diagnosis of bullous lesions in diabetic patient must include an appropriate search for infection, especially fungi. Histopathological and mycological examination is necessary for correct diagnosis and identi cation of the fungal species.