Erysipelas

ERYSIPELAS: http://emedicine.medscape.com/article/1052445-workup#a0723
S. PYOGENES:
http://www.losmicrobios.com.ar/microbios/streptococcus%20grupo%20A.html
BACKGROUND
Erysipelas is a bacterial skin infection involving the upper dermis that characteristically extends into the superficial cutaneous lymphatics. Erysipelas has been traced back to the Middle Ages, where it was referred to as St.Anthony's fire, named after the Christian saint to whom those afflicted would appeal for healing. Around 1095, the Order of St. Anthony, a Roman Catholic congregation, was formed in France to care for those with the ailment. At the time, several diseases were likely grouped under this eponym, including ergotism and herpes zoster (shingles). Historically, erysipelas occurred on the face and wascaused by Streptococcus pyogenes. Currently, the predominance of cases involve the legs, and although S pyogenes is still the most likely etiology, other bacteria, including non–group A Streptococcus, Staphylococcus, and even gram-negative species can be responsible.
PATHOPHYSIOLOGY
Bacterial inoculation into an area of skin trauma is the initial event in developing erysipelas. Thus, local factors,such as venous insufficiency, stasis ulcerations, inflammatory dermatoses, dermatophyte infections, insect bites, and surgical incisions, have been implicated as portals of entry. The source of the bacteria in facial erysipelas is often the host's nasopharynx, and a history of recent streptococcal pharyngitis has been reported in up to one third of cases. Other predisposing factors includediabetes, alcohol abuse,[1] HIV infection, nephrotic syndrome, other immunocompromising conditions, and vagrant lifestyle.
Preexisting lymphedema is a clear-cut risk factor for erysipelas. Recurrent erysipelas complicating the lymphedema from breast cancer treatment is well documented.[2, 3] Lymphoscintigraphy in patients with a first-time episode of lower extremity erysipelas has documented lymphaticimpairment in both affected and nonaffected legs. Thus, subclinical lymphatic dysfunction is a risk factor for erysipelas.[4]
In erysipelas, the infection rapidly invades and spreads through the lymphatic vessels. This can produce overlying skin "streaking" and regional lymph node swelling and tenderness. Immunity does not develop to the inciting organism.
Frequency
United States
Isolatedcases are the rule with erysipelas, although epidemics have been reported. The incidence of erysipelas declined throughout the mid-20th century, possibly due to antibiotic development, improved sanitation, and decreased virulence.[5] The change in distribution from the face to the lower extremities is most likely related to an aging population with risk factors such as lymphedema. Approximately 85% ofcases of erysipelas occur on the legs rather than the face.
International
Erysipelas is somewhat more common in European countries. Isolated cases are still the rule, and distribution and etiology remain similar to that in the United States.
Mortality/Morbidity
The most common complaints during the acute infection include tenderness of the involved area, fever, chills, and swelling.Predisposed patients often develop local recurrence, and this can lead to disfiguring and disabling healing reactions, such as elephantiasis nostras verrucosa. This chronic warty, edematous condition is caused by lymphatic destruction from repeated infection. Death as a direct result of erysipelas is exceedingly rare.
Race
Erysipelas infections affect persons of all races.
Sex
Erysipelas has beenreported to be more common in females, but occurring at an earlier age in males, likely because of their more aggressive activities and resultant skin injuries. Other studies indicate that predisposing factors, rather than gender, account for any male/female differences in incidence.
Age
Cases of erysipelas have been reported in all age groups, but it does appear that infants, young children, and...