Severe and Progressive Cellulitis Caused by Serratia marcescens Following a Dog Scratch

Cutaneous Serratia marcescens infection in two dogs

We describe two canine cases of cutaneous infection caused by Serratia marcescens. A 2-year-old castrated male mixed dog (Case 1) presented with multiple ulcerations on the dorsal trunk, which were observed 4 days after shampooing. A 4-year-old male wolf shepherd mix dog (Case 2) presented with ulceration and purulent discharge on the nasal bridge. Cytological examination of both cases revealed pyogranulomatous inflammatory cells with rod-like infectious agents identified as S. marcescens in aerobic bacterial culture. Both patients were treated with oral antibiotics and topical chlorhexidine. Case 1 received enrofloxacin 10 mg/kg once daily for 1 week, followed by trimethoprim/sulfamethoxazole 15 mg/kg twice daily for 3 weeks. Case 2 received doxycycline 10 mg/kg twice daily for 4 weeks. No skin lesions were detected 2 weeks after the initial administration. The antibiotics were discontinued after a total 4 weeks of administration, and the skin lesions did not reappear.

Acquired perforating dermatosis with associated complicated cellulitis and amputation in a hemodialysis patient

Introduction: Cutaneous manifestations related to chronic kidney disease (CKD) are common and associated with high morbidity. Acquired perforating dermatosis (APD) occurs mostly in diabetic or CKD patients, namely those undergoing hemodialysis. Case report: A 58-year-old male with type 2 diabetes, with long-term insulin use, several microvascular and macrovascular complications, and on maintenance hemodialysis for 5 years presented with a 1-week history of painful, pruritic, umbilicated papules and some punctiform necrotic lesions on his left forearm, both hands, and both amputation stumps. There was no evidence of infection or vascular alterations, and the patient was not responsive to an initial course of topical corticosteroid. These lesions rapidly evolved to larger, coalescent necrotic injuries, with aggravated pain, intense left-hand skin peeling, and the appearance of similar lesions in the trunk, requiring hospital admission. Calciphylaxis and APD were suspected. Skin biopsy was performed and directed treatment initiated, including intradialytic sodium thiosulfate. Histology findings were compatible with APD and also excluded findings suggestive of vasculitis or calciphylaxis. Soon after, difficult-to-treat cellulitis of the left hand and forearm progressed to critical ischemia and amputation. Microbiology analysis revealed Serratia marcescens as the causative agent. Discussion: To our knowledge, there are no previously described cases of APD-related cellulitis. Its treatment can be particularly challenging, as lesions can persist and relapse, and chronic scars can develop. S. marcescens behaves as an opportunistic and difficult-to-treat pathogen, complicating the prognosis. Conclusion: APD can be associated with cellulitis and all of its complications in patients with underlying severe vasculopathy. Awareness of this complication in APD with early referral and aggressive treatment might improve the outcomes and quality of life of such patients.