Erysipelas is localised skin infection caused by Streptococcus pyogenes.

In simple terms, it is a more superficial, limited version of cellulitis.

• Cellulitis refers to infection of the dermis and subcutaneous tissue.
• Erysipelas refers to infection of the dermis and upper subcutaneous tissue

Risk factors

• Previous erysipelas/cellulitis
• Venous insufficiency
• Immune deficiency (e.g. Diabetes, HIV, Alcoholism)
• Breaks in skin barrier (bites, ulcers, psoriasis, eczema)
• Obesity
• Fissured toes or heels due to athlete's foot or tinea pedis - cause skin breakage allowing entry of infective organisms.

Clinical features

• Borders are sharply defined and affected skin is raised, swollen, firm, erythematous and pruritic.
• Commonly affects the lower limbs. If face involved can have 'butterfly' distribution over the cheeks and the bridge of the nose.

If face affected, this source of infection is usually the nasopharynx (possibly recent nasopharyngeal infection).

Investigations