Blistering distal dactylitis.

A 4-year-old girl presented to our dermatology clinic with erythema and bullae on the right foot for 4 days. She did not complain of pain or pruritis. She had no history of recent upper respiratory tract infection, trauma or medication use. Physical examination showed that the patient was afebrile and appeared well; she did not have any superficial lymphadenopathy. We observed multiple tense fluid-filled bullae with edematous erythema over the right first metatarsophalangeal joint and sole of the foot (Figure 1). Her white blood cell count and neutrophil percentage were normal. We diagnosed blistering distal dactylitis and treated the patient with puncture of the bullae, topical 5% povidone–iodine solution and oral amoxicillin. Bacterial culture from the bullous fluid later grew group A β-hemolytic Streptococcus. The lesions resolved completely in 10 days.

Figure 1:

Tense, fluid-filled bullae with edematous erythema (A) overlying the right first metatarsophalangeal joint and (B) on the sole of the foot of a 4-year old girl with blistering distal dactylitis.

Blistering distal dactylitis is a superficial bacterial infection, typically caused by group A β-hemolytic Streptococcus or Staphylococcus aureus. It usually affects children aged 2–16 years,1 but can occur in infants and adults. Blistering distal dactylitis usually presents as tense bullae on an erythematous base over the palmar aspect of the finger or toe, which may extend dorsally to involve lateral nail folds and can also affect the hands and feet.2

Patients are systemically well, afebrile and do not have lymphadenopathy. The lesions usually develop over a few days, and are not painful, pruritic or fragile, unlike bullous impetigo. They are usually unilocular blisters, unlike herpetic whitlow.3 Other differential diagnoses include contact dermatitis, posttraumatic blisters, burns, erythema multiforme, insect bites and stings, and epidermolysis bullosa.4 A Gram stain and bacterial culture of the bullae fluid are diagnostic.

Drainage with a sterile needle, leaving the blister wall intact, is suggested for tense bullae. Wet dressings with a topical antibiotic solution can be used. Patients should be treated with systemic antibiotic therapy for both group A β-hemolytic Streptococcus and S. Aureus. Patients have been treated successfully with amoxicillin, cephalexin or trimethoprim–sulfamethoxazole, but also with amoxicillin-clavulanate in cases of β-lactamase resistance.1,2,4,5 Recurrence is not usually reported.