Infectious diseases seem to be omnipresent in the Ped ED and, thus, have their own dedicated Category of the PedEMMorsels.  Additionally, unusual dermatologic eruptions are also quite prevalently encountered when caring for children (see Approach to Rash).  While individually each category is fun to think about, the excitement more than doubles when they occur concurrently (perhaps I am being facetious). Let’s review Blistering Distal Dactylics! (say that 6 times fast in a row – I dare you)

Blistering Distal Dactylitis: What It Is

• Superficial infection of the distal finger (just like the name would imply)
• Tense bulla forms over the volar aspect / finger pad [Tessaro, 2016]
  • May extend dorsally to the lateral nail folds.
  • Oval shaped
  • Erythematous base
  • Often a singular lesion
• Filled with purulent material (yuk).

• Caused by:
  • Group A Streptococcus pyogenes
    • Most common pathogen
    • Unclear how it causes bullae to develop
    • Don’t forget other interesting Strep Infections:
      • Intertrigo
      • Perianal Strep
  • S. aureus
    • Less common, but known to cause bullous disease (see Staph Scalded Skin)
    • Multiple lesions may predict infection with S. aureus.
    • Rarely is MRSA implicated. [Fretzayas, 2011]
  • S. epidermidis 
  • Group B Streptococcus

• Typically affects kids 2 years to 16 years, but has been shown in children <2 years as well. [Lyon, 2004]

Blistering Distal Dactylitis: Ddx

• Herpetic Whitlow
• Burns
• Bullous impetigo
• Paronychia
• Insect bites
• Blistering disorders
• Dyshidrotic eczema
• Friction blisters and other mechanical irritants

Blistering Distal Dactylitis: Diagnosis It!

• Clinical diagnosis for the most part.
  • Consider other etiologies like Herpetic Whitlow.
  • May have concurrent infection at another remote site (ex, URI, pharyngitis).
  • Multiple lesions suggests Staph as causative agent.
• Can confirm with testing:
  • Gram-stain and culture of debris and fluid from blister.
  • May perform rapid strep testing on fluid/debris. [Cohen, 2014; Wollner, 2014]
    • Rapid Strep Test has similar test characteristics/performance as it does when applied to patients with pharyngitis.

Blistering Distal Dactylitis: Treat It!

• Local Wound Care
  • No definitive recommendations for incision and drainage, but often the blister is unroofed to collect specimen. [Tessaro, 2016]
  • Once unroofed, wet-to-dry dressings are appropriate.
• Systemic Antibiotics
  • Coverage for strep and staph is paramount.
    • Beta-lactamase-resistant antibiotic often selected.
    • Empiric covered for MRSA is not likely beneficial at this point, but keep local resistance patterns in mind.
  • 10 Day course often cited.
  • Topical antibiotics alone are inadequate.

References