Medication Summary

No controlled trials of antimicrobial therapy have been conducted for pharyngitis caused by A. haemolyticum. Many patients with pharyngitis have been treated with 1 dose of intramuscular penicillin or 7-10 days of erythromycin or oral penicillin.^[5]Antibiotic sensitivity testing reveals that most strains are resistant to trimethoprim-sulfamethoxazole; tetracycline resistance has been observed in 30% of strains tested.^{[22, 71]}An isolate reported in 2006 was also resistant to ciprofloxacin.^[45]Virtually all strains of A. haemolyticum studied so far are sensitive to erythromycin, azithromycin, gentamicin, and clindamycin.^{[22, 72]}The majority of isolates are susceptible to penicillin, although tolerance has been reported. Accordingly, macrolides are now considered the drugs of choice.^{[5, 6, 58]}

Penicillin treatment failures also may be related to the ability of A. haemolyticum to invade HEp-2 cells (immortalized upper respiratory epithelial cells) and survive there for 4 days, thus creating an intracellular reservoir of bacteria.^[59]Macrolides achieve much higher intracellular concentrations than penicillin.^{[59, 73, 74]}

More serious systemic infections have been treated successfully with high-dose intravenous beta-lactams (eg, penicillin, ampicillin, amoxicillin, cefuroxime, cefotaxime). Vancomycin is also an acceptable choice for serious infections; however, 1 strain carries the vanA gene, which is resistant to vancomycin.^[75]Antibiotic selection should be based on antibiotic sensitivity testing because no clinical trials of treatment of systemic infections have been conducted.

Class Summary

Although antibiotic therapy decreases the duration of symptoms, whether it prevents sequelae of pharyngeal infection is not known.

Erythromycin ethylsuccinate (E.E.S., EryPed)

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Erythromycin inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, arresting RNA-dependent protein synthesis. It is for the treatment of staphylococcal and streptococcal infections.

In children, age, weight, and severity of infection determine proper dosage. When twice-daily dosing is desired, half of the total daily dose may be taken every 12 hours. For more severe infections, double the dose. While no controlled studies have been performed, erythromycin has been effective in case series and most strains are susceptible.

Azithromycin (Zithromax)

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Azithromycin acts by binding to the 50S ribosomal subunit of susceptible microorganisms and blocks dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Nucleic acid synthesis is not affected. It concentrates in phagocytes and fibroblasts as demonstrated by in vitro incubation techniques. In vivo studies suggest that concentration in phagocytes may contribute to drug distribution to inflamed tissues. Azithromycin treats mild-to-moderate microbial infections. A shorter course and daily dosing make this a good alternative for patients who are sensitive to penicillin.

Clindamycin (Cleocin)

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Clindamycin is a semisynthetic antibiotic produced by the 7(S)-chloro-substitution of 7(R)-hydroxyl group of the parent compound lincomycin. It inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. It widely distributes in the body without penetration of the CNS. Clindamycin is protein bound and is excreted by the liver and kidneys.

It is an oral or parenteral antibiotic for anaerobic or susceptible streptococcal, pneumococcal, or staphylococcal species. It is considered to have good absorption into the bloodstream in both oral and parental forms.

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Media Gallery

Rash associated with pharyngitis caused by Arcanobacterium haemolyticum. Note the erythematous nature of the rash.
The rash associated with pharyngitis caused by Arcanobacterium haemolyticum is most prominent on the extremities. Note the rash on the upper limbs.
The rash associated with pharyngitis caused by Arcanobacterium haemolyticum is most prominent on the extremities. Note the rash on the lower limbs.
Rash associated with pharyngitis caused by Arcanobacterium haemolyticum. Note the significant involvement of the extremities and the relative sparing of the face.

of 4

Author

Nicole Ufkes Medical University of South Carolina College of Medicine

Nicole Ufkes is a member of the following medical societies: American Medical Association, American Medical Women's Association, American Society of Tropical Medicine and Hygiene

Disclosure: Nothing to disclose.

Coauthor(s)

Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Specialty Editor Board

David F Butler, MD Former Section Chief of Dermatology, Central Texas Veterans Healthcare System; Professor of Dermatology, Texas A&M University College of Medicine; Founding Chair, Department of Dermatology, Scott and White Clinic

David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Association of Military Dermatologists, Phi Beta Kappa, Texas Dermatological Society

Disclosure: Nothing to disclose.

Paul Krusinski, MD Director of Dermatology, Fletcher Allen Health Care; Professor, Department of Internal Medicine, University of Vermont College of Medicine

Paul Krusinski, MD is a member of the following medical societies: American Academy of Dermatology, American College of Physicians, Society for Investigative Dermatology

Disclosure: Nothing to disclose.

Chief Editor

William D James, MD Paul R Gross Professor of Dermatology, Vice-Chairman, Residency Program Director, Department of Dermatology, University of Pennsylvania School of Medicine

William D James, MD is a member of the following medical societies: American Academy of Dermatology, Society for Investigative Dermatology

Disclosure: Received income in an amount equal to or greater than $250 from: Elsevier; WebMD<br/>Served as a speaker for various universities, dermatology societies, and dermatology departments.

Additional Contributors

Robin Travers, MD Assistant Professor of Medicine (Dermatology), Dartmouth University School of Medicine; Staff Dermatologist, New England Baptist Hospital; Private Practice, SkinCare Physicians

Robin Travers, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Informatics Association, Massachusetts Medical Society, Women's Dermatologic Society, Medical Dermatology Society

Disclosure: Nothing to disclose.

Gregory J Raugi, MD, PhD Professor, Department of Internal Medicine, Division of Dermatology, University of Washington at Seattle School of Medicine; Chief, Dermatology Section, Primary and Specialty Care Service, Veterans Administration Medical Center of Seattle

Gregory J Raugi, MD, PhD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Kord Honda, MD Fellow in Dermatopathology, Division of Dermatology, Department of Medicine, University of Cincinnati

Kord Honda, MD is a member of the following medical societies: Phi Beta Kappa

Disclosure: Nothing to disclose.

Kyle L Horner, MD, MS Physician, Grace Dermatology and Micrographic Surgery, Lebanon, OR

Kyle L Horner, MD, MS is a member of the following medical societies: American Academy of Dermatology, American College of Mohs Surgery

Disclosure: Nothing to disclose.

Acknowledgements

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous author, Richard Miller, MD, to the development and writing of this article. The authors would like to thank Jan Hirschmann for his critical review of this article and Richard Miller, MD, for graciously providing the images.