Can Impetigo Occur on the Arm?
Yes, impetigo absolutely can and commonly does occur on the arm, as it typically affects exposed areas of the body, most frequently the face and extremities. 1
Anatomical Distribution of Impetigo
Impetigo characteristically develops on exposed body surfaces where minor trauma, abrasions, or insect bites allow bacterial entry into the skin. 1
The arms are among the most common sites for impetigo lesions, second only to the face. 1, 2
- The infection usually occurs on exposed areas of the body, with the face and extremities (including arms) being the most frequently affected sites 1
- Lesions remain well-localized but are frequently multiple across these exposed areas 1
- Both bullous and nonbullous forms can develop on the arms 1, 3
Pathophysiology on Extremities
The mechanism by which impetigo develops on the arms follows a predictable pattern:
- Causative organisms (β-hemolytic streptococci and/or S. aureus) initially colonize unbroken skin on the extremities 1
- Inoculation of surface organisms into the skin occurs through abrasions, minor trauma, or insect bites—all common on the arms 1
- Colonization precedes the development of lesions by approximately 10 days 1
Clinical Presentation on Arms
When impetigo occurs on the arms, it presents with the same characteristic features as elsewhere:
- Nonbullous impetigo (70% of cases) begins as erythematous papules that rapidly evolve into vesicles, pustules, and finally thick honey-colored crusts 2, 3
- Bullous impetigo (30% of cases) presents as fragile, thin-roofed vesicopustules that can form large, flaccid bullae 2, 3
- Lesions may be multiple on the arms and can spread to other exposed areas 1
Treatment Considerations for Arm Lesions
Treatment for impetigo on the arms follows standard protocols:
- For localized arm lesions: Topical mupirocin 2% ointment applied three times daily for 5-7 days is first-line therapy 4, 2
- For extensive arm involvement or multiple sites: Oral antibiotics such as dicloxacillin or cephalexin for MSSA, or clindamycin/TMP-SMX for MRSA 4, 2
- Lesions should be kept covered with clean, dry bandages to prevent spread 4, 2
Common Pitfalls
A key clinical caveat is that the arms' exposure to environmental trauma makes them particularly susceptible to impetigo, especially in children during summer months when skin is more exposed and minor injuries are common. 1