Is there a link between myocardial infarction (MI) and cellulitis of the leg?

Direct Link Between MI and Leg Cellulitis

There is no direct causal link between myocardial infarction and cellulitis of the leg, but patients with leg cellulitis—particularly when complicated by bloodstream infection—face a significantly elevated short-term risk of MI due to systemic inflammation.

The Inflammatory Connection

The relationship operates primarily through infection-triggered inflammation rather than a direct pathophysiologic link:

• Bloodstream infections (which can complicate cellulitis) dramatically increase MI risk in the immediate post-infection period, with the highest risk occurring 1-7 days after infection (adjusted incidence rate ratio: 9.67) 1
• The magnitude of systemic inflammation directly correlates with cardiovascular risk: patients with peak C-reactive protein >300 mg/L show a 21-fold increased MI risk in the week following bloodstream infection 1
• This elevated cardiovascular risk returns to baseline after 28 days, indicating a transient inflammatory mechanism rather than permanent structural changes 1

Pathophysiologic Mechanisms

When cellulitis progresses to systemic infection, several mechanisms can precipitate MI:

• Systemic inflammation promotes endothelial dysfunction and atherosclerosis through increased mediators of inflammation, similar to mechanisms seen in other inflammatory conditions like psoriasis and rheumatoid arthritis 2
• Infection-related effects on platelets—including aggregation and release of vasoactive substances—can trigger coronary thrombosis and vasospasm 3
• Coronary arteritis from blood-borne infectious agents has been demonstrated in necropsy and biopsy material, with implications for both vasospasm and thrombosis 3

Clinical Implications for Leg Cellulitis

The primary concern is preventing progression to bloodstream infection:

• Prompt diagnosis and treatment of foot infections are critical to avoid complications including systemic infection that could trigger cardiovascular events 2
• Patients with peripheral artery disease (PAD) and foot infection face nearly 3-fold higher risk of major complications compared to either condition alone 2
• Toe web bacterial colonization (Staphylococcus aureus and/or beta-hemolytic streptococci) carries a 29-fold increased risk of developing cellulitis (OR: 28.97), making this a critical intervention point 4

High-Risk Patient Identification

Certain patients with cellulitis warrant heightened cardiovascular monitoring:

• Those with signs of systemic infection (fever >38°C, tachycardia >90/min, respiratory rate >20/min, WBC >12,000 or <4,000/mcL) should be monitored for cardiovascular complications 2
• Patients with PAD and cellulitis require prompt referral to interdisciplinary care teams given their substantially elevated complication risk 2
• Previous saphenectomy increases cellulitis risk 8-fold (OR: 8.49), and these patients may have underlying cardiovascular disease 4

Prevention Strategies

To minimize both cellulitis occurrence and potential cardiovascular complications:

• Address toe web intertrigo and bacterial colonization aggressively, as this represents the most modifiable high-risk factor for lower extremity cellulitis 4
• Manage leg erosions, ulcers, and tinea pedis interdigitalis, which independently increase cellulitis risk 4
• Recognize that each cellulitis episode causes lymphatic damage, potentially creating a cycle of recurrent infections with cumulative cardiovascular risk 5, 6

Common Pitfall

Do not dismiss cardiovascular symptoms in patients with active cellulitis or recent bloodstream infection as unrelated conditions. The 2-week period following significant infection represents a window of substantially elevated MI and stroke risk that requires clinical vigilance 1. Consider cardiac biomarkers and ECG in patients with cellulitis who develop chest pain, dyspnea, or other concerning symptoms, particularly if systemic inflammatory markers are markedly elevated.