Does a Patient's Skin Infection Emit an Odor?
Yes, certain skin infections can emit a characteristic and sometimes unpleasant odor, which serves as an important clinical indicator of infection severity, tissue involvement, and specific pathogenic organisms.
When Odor Indicates Infection
Diabetic Foot Infections and Chronic Wounds
A fetid odor from a chronic wound or diabetic foot ulcer is a recognized clinical sign that should raise suspicion for infection, even when other inflammatory signs are ambiguous. 1
- In diabetic foot infections, a fetid odor is specifically mentioned as one of the unusual circumstances where it becomes difficult to determine if a chronic wound is infected 1
- This is particularly relevant when the foot is ischemic, has abnormal skin coloration, friable granulation tissue, or when an otherwise properly treated ulcer fails to show healing progress 1
- In these cases with fetid odor, a brief culture-directed course of antibiotic therapy may be appropriate 1
Congenital Ichthyoses and Barrier Dysfunction
Patients with impaired epidermal barrier function, such as those with congenital ichthyoses, commonly develop a characteristic and sometimes unpleasant smell due to altered bacterial and fungal colonization. 1
- The impaired epidermal barrier significantly modifies bacterial or fungal skin colonization patterns 1
- This characteristic smell is illustrated in many forms of congenital ichthyoses and reflects changes in the skin microbiome 1
- Bacterial cutaneous infections in these patients may involve Staphylococcus aureus and group A streptococci 1
Clinical Significance of Odor
As a Warning Sign
Pus or drainage that develops a foul odor requires immediate medical attention, as it indicates advancing infection or tissue necrosis. 2
- Foul odor combined with increasing drainage suggests worsening infection 2
- This finding should prompt urgent evaluation, particularly in high-risk patients 2
Necrotizing Infections
While not explicitly stated in the guidelines, necrotizing soft tissue infections often produce distinctive odors due to:
- Tissue necrosis and gangrene, which are features of moderate to severe diabetic foot infections 1
- Anaerobic bacterial involvement, which is common in polymicrobial necrotizing infections 1
- Deep tissue abscesses involving muscle, tendon, joint, or bone 1
Common Pitfalls to Avoid
Do not dismiss odor as merely a hygiene issue—it may be the only early indicator of deep tissue infection in patients with neuropathy or impaired sensation. 1
- Diabetic patients with peripheral neuropathy may not experience typical pain or tenderness, making odor a critical diagnostic clue 2
- Failure to recognize odor as a sign of infection can delay treatment, which is most effective when initiated within 24-48 hours 2
Do not rely solely on surface appearance when odor is present—probe wounds to assess depth and extent of infection. 1
- In necrotizing fasciitis, probing wound edges with a blunt instrument permits ready dissection of superficial fascial planes well beyond visible wound margins 1
- The wooden-hard feel of subcutaneous tissues combined with odor suggests deep fascial involvement 1
When to Seek Immediate Medical Care
Any patient with a malodorous wound who also exhibits systemic signs requires urgent evaluation: 2, 3