Chemotherapy-Induced Pseudocellulitis Without Prior Radiation Exposure

Importance Chemotherapy-induced pseudocellulitis is an ill-defined term for a poorly understood phenomenon. Encompassing a myriad of cellulitis-mimicking oncologic adverse cutaneous drug reactions (ACDRs), pseudocellulitis may be difficult to diagnosis, and the lack of treatment guidance may mean unnecessary antibiotic exposure and interruptions to oncologic care. Objectives To use case reports to characterize the various cellulitis-mimicking reactions caused by chemotherapeutic medications, to understand how these reactions affect patient care (ie, antibiotic exposure and interruptions to oncologic treatment), and to make recommendations for improved diagnosis and care of patients with chemotherapy-induced pseudocellulitis. Evidence Review A systematic review of case reports of patients with pseudocellulitis was performed. Reports were identified through database searches using PubMed and Embase, with subsequent reference searches. Included publications described at least 1 case of chemotherapy-induced ACDR and used the term pseudocellulitis or showed evidence of cellulitis mimicry. Cases of radiation recall dermatitis were excluded. Data were extracted from a total of 32 publications representing 81 patients diagnosed with pseudocellulitis. Findings Of the 81 cases (median [range] age, 67 [36-80] years; 44 [54%] male patients), most were associated with gemcitabine use; pemetrexed use was reported less frequently. Only 39 were considered to be true chemotherapy-induced pseudocellulitis. These cases resembled infectious cellulitis and did not meet diagnostic criteria for any known diagnoses; therefore, these were described solely as pseudocellulitis. Of this group, 26 patients (67%) had been administered antibiotics before the correct diagnosis was made, and 14 patients (36%) experienced interruptions to their oncologic treatment plans. Conclusions and Relevance This systematic review found a variety of chemotherapy-induced ACDRs that mimic infectious cellulitis, including a group of reactions termed pseudocellulitis that do not meet criteria for other diagnoses. A more universally accepted definition and clinical research on chemotherapy-induced pseudocellulitis would allow for more accurate diagnosis, effective treatment, antibiotic stewardship, and continuation of oncologic treatment.