Medication Summary
Oral erythromycin remains the drug of choice for bacillary angiomatosis, with skin lesions often gradually fading over a period of 4 weeks. If the lesions persist, however, even in diminished form, medication can be changed to tetracycline. If the infection appears to be serious, adding a bactericidal medication, such as a third-generation cephalosporin or an aminoglycoside, may be prudent during the initial 3 weeks of therapy. According to a report from Chile, a patient with HIV infection and bacillary angiomatosis caused by B quintana responded favorably to azithromycin plus ciprofloxacin started together with antiretroviral therapy. [54]
The Infectious Disease Society 2014 Guidelines suggest erythromycin 500 mg 4 times a day or doxycycline 100 mg twice a day to be used for at least 2 weeks and up to 2 months. [5]
Antibiotics
Class Summary
Empiric antimicrobial therapy should cover all likely pathogens in the context of the clinical setting.
Tetracycline
Tetracycline inhibits bacterial protein synthesis by binding with 30S and possibly 50S ribosomal subunits. Primarily bacteriostatic, it has anti-inflammatory activity and is active against a wide range of gram-positive and gram-negative organisms.
Erythromycin (Ery-Tab, E.E.S., Erythrocin)
Erythromycin is a highly bacteriostatic macrolide antibiotic isolated from a Streptomyces strain. Its spectrum is between those of penicillin and tetracyclines. The mechanism of action involves binding to the 50S ribosomal subunit and inhibiting microbial protein synthesis.
Clarithromycin (Biaxin)
This agent is a highly bacteriostatic, semisynthetic macrolide. A 6-methoxy erythromycin, clarithromycin inhibits bacterial growth, possibly by blocking dissociation of peptidyl transfer RNA (tRNA) from ribosomes, causing RNA-dependent protein synthesis to arrest. It has a spectrum between those of penicillin and tetracyclines.
Azithromycin (Zithromax, Zmax)
Azithromycin is a highly bacteriostatic macrolide with a spectrum between those of penicillin and tetracyclines. Its mechanism of action involves binding to the 50S ribosomal subunit and inhibiting microbial protein synthesis.
Doxycycline (Vibramycin, Monodox, Adoxa, Doryx)
Doxycycline is a bacteriostatic antibiotic that inhibits protein synthesis and thus bacterial growth by binding to 30S and possibly 50S ribosomal subunits of susceptible bacteria. It is an important form of tetracycline that is effective in twice-daily dosing.
Rifampin (Rifadin)
This is a bactericidal antibiotic that inhibits bacterial protein synthesis by inhibiting DNA-dependent RNA polymerase. It is useful in immunocompromised patients with severe disease.
Trimethoprim and sulfamethoxazole (Bactrim, Bactrim DS, Septra DS)
This synthetic, antibacterial combination product discourages bacterial growth by inhibiting the synthesis of dihydrofolic acid.
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A 35-year-old retrovirus-negative Mexican immigrant who had undergone recent splenectomy for idiopathic thrombocytopenic purpura, with multiple violaceous nodules on his trunk.
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Many blood vessels of varying dimensions lined by swollen endothelial cells that contain bacilli. An infiltrate of acute and chronic inflammatory cells as well as fibrin deposition is noted in places (hematoxylin and eosin, X80).
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A 40-year-old HIV-positive homosexual man with lichenoid cutaneous plaques on his upper extremities.
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Lesion showing large masses of blood vessels of markedly varying dimensions lined by swollen endothelial cells. The tissue is friable with evident fragmentation during processing (hematoxylin and eosin, X23).
