Among the most distressing outcomes in complaints in patients with tissue injuries is the onset of wound odors. Although these smells might be barely noticeable in some wound types, others will give off very offensive odors. Apart from causing significant psychological distress to affected patients due to social isolation, malodorous wounds may also indicate a poor healing response or an infection.

Why Do Wounds Produce Odors?

A wound develops an odor as a result of metabolic processes occurring at the injury site. The key factors that contribute to the development of offensive or unpleasant wound odors include tissue degradation and the activity of anaerobic or aerobic microorganisms. Chronic wounds are especially susceptible to producing wound odors as they provide a more suitable environment for microbial colonization. Sufficient quantities of slowly healing tissues, combined with poor wound care practices will allow the bacteria in wounds to release various chemicals that cause foul smells in wounds.

What Are the Causes of Malodorous Wounds?

Foul-smelling wounds are caused by the activities of various categories of bacteria including those that require oxygen for metabolic processes (aerobes), and those that don’t (anaerobes). Common aerobes known to cause putrid wounds include proteus, klebsiella, and pseudomonas. Anaerobic organisms such as prevotella, Bacteroides fragilis, fusobacterium, and clostridium perfringens release foul-smelling chemical compounds (e.g., putrescine and cadaverine) after interacting with wound tissues. 

Classifying Wound Odors

While there is no universal consensus for classifying wound odors, some wound care experts use the distance at which the effluent from a wound can be perceived to grade its severity. The presence or absence of a wound dressing also contributes to this grading. Wound odor grading includes the following categories:

Very strong malodor: This is immediately perceived on entering a room with a patient with a wound. The offensive smell can be detected at a distance of 6-10 feet, even with the wound completely wrapped in a dressing.

Strong malodor: A strong smell can be detected at a distance of 6-10 feet only when the dressing is removed, or the wound is partially exposed.

Moderate malodor: The odor is only noticeable close to the wound with a dressing intact.

Slight malodor: This is similar to a moderately odorous wound however it can only be detected near a partially exposed wound or one without a dressing.

No odor: This wound type has no odor even close to the wound with or without a dressing present.

Wound Odor: When to Worry

While a healing wound might have a smell under normal conditions, a distinctly malodorous wound should make any wound care professional cautious. Offensive odors from a wound site are usually a sign of bacterial colonization, and infection. Other clinical signs and symptoms that should further arouse the suspicion of the wound care personnel managing the wound are a fever, pain, swelling around the wound site, and a patient who appears generally unwell.

Predicting Infectious Pathogens by Odor

With increasing clinical experience, wound care professionals might be able to identify smells that indicate a serious infective process and this will allow them to intervene early. Clostridium has a very pungent smell like feces, Bacteroides has an acrid smell, proteus smells like ammonia while pseudomonas has an odor described as “sickly sweet.” 

Why Is Wound Odor a Problem?

In addition to other signs of poor wound healing, an offensive wound odor is an indication a wound might be infected. An infected wound will heal more slowly than an uninfected one making the affected patient more susceptible to wound healing complications. Consequently, any unusual, offensive wound odors must be investigated as soon as they are detected to improve wound healing outcomes.

Treatment Strategies for Wounds with Offensive Odors

The effective management of wound odors is based on proper wound debridement and infection control. Strict local wound care practices with cleansing and removal of dead tissues prevent their degradation by bacteria and any resultant odors. Antibiotic therapy also contributes to reducing malodor by inhibiting the growth of microorganisms that produce foul-smelling wound exudate. 

Apart from the above-mentioned techniques used to eliminate wound odor, using odor-limiting wound dressings is a viable option in more severe cases. Wounds will require constant cleaning, and dressings to lessen the exudate they produce and therefore reduce any associated unpleasant smells. Activated charcoal dressings are particularly effective in controlling wound odor in various categories of patients. Further, wound care professionals can suggest the use of external deodorants to mask wound odors in addition to the above-mentioned methods.

Tips and Precautions for Improving Wound Odors

The following precautions will enable wound care experts to avoid/deal with complaints of unpleasant wound odors by their patients:

• Regular wound cleansing, and removal of devitalized tissues
• Frequent wound dressings unless otherwise indicated
• Counseling patients to practice proper hygiene
• Use of odor masking products
• The use of cleansers that penetrate biofilms and sanctuary sites for microorganisms
• Biocides to eliminate organisms at the wound sites