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Updated: Jun 17, 2026
Studying the Stoichiometry of Epidermal Growth Factor Receptor in Intact Cells using Correlative Microscopy
Published on: September 11, 2015
Microbiological analysis of epidermal growth factor receptor inhibitor therapy-associated paronychia
1Department of Dermatology and Allergy, Ludwig-Maximilian University, Munich, Germany.
Background:
Paronychia is a well-known, but difficult to treat cutaneous toxicity associated with epidermal growth factor receptor (EGFR) inhibitor therapy. Although bacterial and fungal infections as well as mechanical trauma may play a role as co-pathogens, there is no good basis for an empirical antimicrobial chemotherapy in these patients.
Materials And Methods:
We retrospectively analysed the microbiological results and resistance analysis of 42 cases of EGFR inhibitor-associated paronychia induced by cetuximab.
Results:
We identified 20 different species, among these 72% Gram-positive bacteria, 23% Gram-negative bacteria and 5%Candida species. About half of the microbes identified may be considered as residential bacterial flora of the skin, but isolation of microbes from paronychia may indicate a pathogenic relevance for this type of reaction. Eight of our patients were treated with oral antibiotics, whereas two patients received oral antimycotic therapy. All other cases of paronychia were controlled using topical antiseptic, antibiotic and antimycotic agents.
Conclusion:
Empirical oral antibiotic treatment may be performed with oral cephalosporines, ciprofloxacin, levofloxacin or moxifloxacin, as these antimicrobials have high in vitro activity against the majority of the isolated microorganisms and reach high concentrations in the relevant tissue.
Insights
Paronychia, a side effect of epidermal growth factor receptor (EGFR) inhibitor therapy, often involves bacterial and fungal infections. Oral cephalosporines, ciprofloxacin, levofloxacin, or moxifloxacin show high in vitro activity against common pathogens.
Area of Science:
- Oncology
- Dermatology
- Infectious Diseases
Background:
- Paronychia is a common, challenging cutaneous toxicity linked to epidermal growth factor receptor (EGFR) inhibitor treatments.
- While bacterial, fungal, and mechanical factors may contribute, empirical antimicrobial therapy lacks a strong evidence base.
Purpose of the Study:
- To retrospectively analyze microbiological findings and resistance patterns in EGFR inhibitor-associated paronychia.
- To guide appropriate antimicrobial chemotherapy for this EGFR inhibitor side effect.
Main Methods:
- Retrospective analysis of microbiological results from 42 patients with cetuximab-induced paronychia.
- Identification of microbial species and assessment of antimicrobial resistance patterns.
Main Results:
- Identified 20 microbial species: 72% Gram-positive bacteria, 23% Gram-negative bacteria, and 5% Candida species.
- Many isolated microbes are skin commensals, but their presence in paronychia suggests pathogenic relevance.
- Topical treatments were effective for most cases; oral antibiotics or antifungals were used in a minority of patients.
Conclusions:
- Oral cephalosporines, ciprofloxacin, levofloxacin, or moxifloxacin are recommended for empirical treatment.
- These agents exhibit high in vitro activity against prevalent microorganisms and achieve adequate tissue concentrations.