Bacillary angiomatosis is known to be caused by a rickettsial organism; Rochalimaea henselae. This causative agent has been compared with different microorganisms and clinical conditions that appear in similar settings buy have been clearly differentiated from them; e.i.
Cat-scratch disease (Afipia felis), Bartonella bacilliformis, other Rochalimaea sp.,
Kaposi's sarcoma,
Lobular capillary hemangioma,
Angiosarcoma, and Epithelioid
hemangioma. Clinically the
bacillary angiomatosis (BA) skin lesions vary from a single lesion to thousands. The cutaneous lesion appears as a bright-red round papule, subcutaneous nodule, or as a cellulitic plaque. When the lesion is biopsied it tends to blanch-out, bleed, and cause
pain. The patient might present with signs and symptoms of
chills,
headaches,
fever, malaise, and
anorexia with or without
weight loss. The extracutaneous lesions found in BA tend to be from multiple organs affecting from the oral lesions to anal mucosal lesions to widespread visceral lesions. The sites of preference for BA lesion manifestation tend to be the liver, spleen, lymph nodes, and bone. To diagnose
bacillary angiomatosis the physician should prepare a differential diagnosis based primarily on its histopathological and clinical characteristics. To confirm the results from the
stain, electron microscopy can identify the bacillus and pin-point the diagnosis of
bacillary angiomatosis. The lesions presented by BA respond well to
therapy with
erythromycin 500 mg four times daily for a duration of 2 weeks to 2 months. In case of intolerance to
erythromycin the second line of
drug that successfully treats the BA bacillus is doxycyline. If relapses of the BA lesion recur, then a prolonged
antibiotic therapy is necessary and in
AIDS patients the duration may be extended as life-long suppressive
therapy.