– Skin barrier disruption (trauma, abrasions, existing ulcers or chronic wounds, injection drug use, dermatologic conditions [eg, eczema, psoriasis])

– Lymphedema

– Chronic venous stasis or stasis dermatitis

– Obesity

– Immunosuppression

– Diabetes mellitus

– Toe web space abnormalities (eg, tinea pedis)

– Onychomycosis