Swollen toes
Both of this youngster’s big toes were swollen, yet there was no history of trauma or unusual exposure.
Diagnosis: Blistering distal dactylitis
We made a clinical diagnosis of blistering distal dactylitis (BDD), a condition typically caused by infection with Gram-positive bacteria. BDD is generally described as a localized infection of the volar fat pads of one or more fingers. The infection may also occur more proximally on the hand or involve the thumbs or toes.1
Who’s at risk? BDD occurs among children ages 2 to 16 years, although it has been reported in infants as young as 6 months and in adults. No cases have occurred among the elderly.2-7
The most common etiologic agents are group A beta-hemolytic Streptococci. Less commonly reported agents include Staphylococcus aureus, S. epidermidis, group B Streptococci, and MRSA.1,6,8 The presence of multiple bullae may be predictive of infection with S. aureus.9
A clinical diagnosis
Diagnosis is usually made on clinical grounds based on the presence of large, tense, superficial, and typically painful bullae, the base of which may be erythematous. Culture of the blister fluid and the base of an unroofed blister may confirm the presence of a Streptococcus or Staphylococcus species.
Lab tests are typically not required to confirm a diagnosis of BDD. However, wound cultures of blister fluid, rapid antigen testing for group A beta-hemolytic Streptococci, and viral culture or polymerase chain reaction testing for herpes simplex virus may be considered.
Rule these conditions out
Lesions similar to those seen with BDD can be caused by the following infections and irritants:4,5,8
Herpetic whitlow is caused by a herpes simplex virus infection. It presents as a cluster of painful vesicles or ulcers with an erythematous base on the distal part of a finger or toe.
Bullous impetigo is the result of a staphylococcal infection, which produces an epidermolytic toxin leading to bulla formation. Lesions may occur anywhere on the body but are most common on the face.
Irritant or allergic contact dermatitis results from an external topical exposure and is typically localized to the area of contact. The reaction is an eczematous eruption that may include bullae.
Treatment is typically empiric
Treatment of BDD includes wound care with wet-to-dry saline dressings, incision and drainage of the bulla(e), and a systemic beta-lactamase-resistant antibiotic. Topical antibiotics alone are not recommended.7
Our patient was transitioned from intravenous to oral clindamycin, 100 mg every 8 hours, and the bullae were incised and drained. His leukocytosis resolved within 24 hours, and he continued to do well. At follow-up one week later, the patient’s blisters were healing well, and he was playful and eating and drinking normally.
CORRESPONDENCE
C. Randall Clinch, DO, MS, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC 27157; crclinch@wakehealth.edu.
