Bilateral axillary pustules

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Bilateral axillary pustules

J Fam Pract. 2008 April;57(4):253-255

References

1. Elston DM. Epidemiology and prevention of skin and soft tissue infections. Cutis 2004;73:S3-7.

2. Moran GJ, Krishnadasan A, Gorwitz RJ, Fosheim GE, McDougal LK, et al. Methicillin-resistant S. aureus. infections among patients in the emergency department. N Engl J Med 2006;355:666-674.

3. Cohen PR, Kurzrock R. Community-acquired methicillin-resistant Staphylococcus aureus skin infection: An emerging clinical problem. J Am Acad Dermatol 2004;50:277-280.

4. Romero DV, Treston J, O’Sullivan AL. Hand-to-hand combat: Preventing MRSA infection. Adv Skin Wound Care 2006;19:328-333.

5. Moran GJ, Amii RN, Abrahamian FM, Talan DA. Methicillin-resistant Staphylococcus aureus in community-acquired skin infections. Emerg Infec Dis 2005;11:928-930.

6. Cohen PR, Grossman ME. Management of cutaneous lesions associated with an emerging epidemic: Community-acquired methicillin-resistant Staphylococcus aureus skin infections. J Am Acad Dermatol 2004;51:132-135.

7. Naimi TS, LeDell KH, Como-Sabetti K, Borchardt SM, Boxrud DJ, et al. Comparison of community-and health care-associated methicillin-resistant Staphylococcus aureus infection. JAMA 2003;290:2976-2984.

8. Vandenesch F, Naimi T, Enright MC, et al. Community-acquired methicillin-resistant Staphylococcus aureus carrying Panton-Valentine leukocidin genes: worldwide emergence. Emerg Infect Dis 2003;9:978-984.

9. Iyer S, Jones DH. Community-acquired methicillin-resistant Staphylococcus aureus skin infection: A retrospective analysis of clinical presentation and treatment of a local outbreak. J Am Acad Dermatol 2004;50:854-858.

10. Cohen PR. Community-acquired methicillin-resistant Staphylococcus aureus skin infection presenting as a periumbilical folliculitis. Cutis. 2006;77:229-231.

11. Bahrain M, Vasiliades M, Wolff M, Younus F. Five cases of bacterial endocarditis after furunculosis and the ongoing saga of community-acquired methicillin-resistant Staphylococcus aureus infections. Scand J Infect Dis 2006;38:702-707.

12. Herold B, Immergluck L, Maranan M, et al. Community-acquired methicillin-resistant Staphylococcus aureus in children with no identified predisposing risk. JAMA 1998;279:593-598.

13. Siberry GK, Tekle T, Carroll K, Dick J. Failure of clindamycin treatment of methicillin-resistant Staphylococcus aureus expressing inducible clindamycin resistance in vitro. Clin Infect Dis 2003;27:1257-1260.

14. Boyce JM. MRSA patient: proven methods to treat colonization and infection. J Hosp Infect 2001;48:S9-14.

Diagnosis: MRSA folliculitis

We began empiric systemic antibiotic therapy with doxycycline 100 mg daily and topical treatment with clindamycin 1% lotion twice a day. The bacterial culture came back positive for methicillin-resistant Staphylococcus aureus (MRSA) and the organism proved to be tetracycline sensitive.

Staphylococci species have long been the most common causes of skin and soft tissue infections.¹ A recent study in 11 major US cities identified MRSA as the most common cause of acute purulent skin and soft tissue infections in patients presenting to the emergency department.² This rate, however, varied from 15% to 74% in various cities.² Today, clinicians must consider MRSA as a potential causative agent whenever they treat a patient with a skin and soft tissue infection.

FAST TRACK

We immediately considered bacterial folliculitis and hidradenitis suppurativa

Community-acquired MRSA: Don’t expect typical risk factors

Community-acquired MRSA (CA-MRSA) cases differ from hospital-acquired MRSA (HA-MRSA) cases demographically, microbiologically, and clinically. CA-MRSA infections typically occur in young, healthy individuals without traditional MRSA risk factors such as recent hospitalization, residence in a long-term care facility, or prior antibiotic use.^3,4

CA-MRSA outbreaks have been associated with participation in team sports, living in prison, dormitory, or group home settings, IV drug use, sharing personal items, and men who have sex with men.^4,5 However, the prevalence of MRSA infections in patients without any recognized risk factors, like our patient, is increasing.⁶

CA-MRSA is genetically distinct from HA-MRSA in that it contains the Panton-Valentine leukocidin, an important virulence factor, and carries the type IV or type V SCCmec cassette, which resides at a different methicillin-resistant locus.^7,8 CA-MRSA also does not demonstrate the multi-drug resistance typical of HA-MRSA, and these infections tend to be susceptible to most non-beta-lactam antibiotics.⁶

Is it MRSA or another pathogen?

When considering the differential diagnosis of MRSA folliculitis, consider methicillin-susceptible staphylococci species as equally likely pathogens. Gram-negative bacteria, including Pseudomonas aeruginosa, Malassezia furfur, and Candida species are less common, but notable causes of folliculitis. Other causes include eosinophilic folliculitis, non-bacterial/irritant folliculitis, pseudofolliculitis (chronic in-grown hairs), hidradenitis suppurativa, and acne vulgaris.