ERYSIPELAS

Synonyms : St. Anthony’s fire; ignis sacer.

Clinical Presentation :

. Sharply demarkated erythematous or purpuric patch or plaque, sometimes covered by vesicles and/or bullae
. Often accompanied by edema, lymphangitis, lymphadenitis,and fever
. Face and lower extremities involved commonly, usually unilateral
. Lesion is painful

Histopathology :

. Sparse to moderately dense perivascular and interstitial mixed-cell infiltrate of lymphocytes, neutrophils, and few eosinophils
. Erythrocytes extravasated in number
. Widely dilated venules and lymphatics
. Edema of the papillary dermis
. Spongiosis and ballooning of the epidermis sometimes

Patients typically develop symptoms including high fevers, shaking, chills, fatigue, headaches, vomiting, and general illness within 48 hours of the initial infection. The erythematous skin lesion enlarges rapidly and has a sharply demarcated raised edge. It appears as a red, swollen, warm, hardened and painful rash, similar in consistency to an orange peel. More severe infections can result in vesicles, bullae, and petechiae, with possible skin necrosis. Lymph nodes may be swollen, and lymphedema may occur. Occasionally, a red streak extending to the lymph node can be seen.

The infection may occur on any part of the skin including the face, arms, fingers, legs and toes, but it tends to favor the extremities. Fat tissue is most susceptible to infection, and facial areas typically around the eyes, ears, and cheeks. Repeated infection of the extremities can lead to chronic swelling (lymphadenitis).

This disease is mainly diagnosed by the appearance of well-demarcated rash and inflammation. Blood cultures are unreliable for diagnosis of the disease, but may be used to test for sepsis. Erysipelas must be differentiated from herpes zoster, angioedema, contact dermatitis, and diffuse inflammatory carcinoma of the breast.

Erysipelas can be distinguished from cellulitis by its raised advancing edges and sharp borders. Elevation of the antistreptolysin O titre occurs after around 10 days of illness.

Pathophysiology :

. Beta-hemolytic streptococcus is responsible most commonly, Staphylococcus aureus less commonly.

Clinicopathologic Correlation:

Clinical Feature -- Pathologic Feature
Erythema -- Dilated vessels
Purpuric color -- Extravasated erythrocytes
Vesicles and bullae -- Extensive edema of the papillary ,dermis, and/or spongiosis, and ballooning