Blistering Distal Dactylitis in an Adult

Introduction

Blistering distal dactylitis is an infection that most commonly affects children. ¹ A case of blistering distal dactylitis in a 32-year-old male is reported.

Case Report

A 32-year-old Caucasian male presented to clinic with a 3-day history of blisters at the fingertips. These blisters had increased in size after therapy with wraps. The patient denied a history of fever, chills, trauma, new medications, friction to the fingertips, or contacts with skin infection. The patient had a past medical history of autistic disorder, obsessive compulsive disorder, major depressive disorder, anxiety, sinus tachycardia, chronic constipation, and allergic rhinitis. Current medications included senna, lubiprostone, bisacodyl, azelastine nasal spray, diphenhydramine, risperidone, ziprasidone, benztropine, carbamazepine, mirtazapine, valproic acid, clonazepam, desitin, melatonin, acetaminophen, and zinc supplements. On exam, the patient was afebrile. Examination of the hands revealed tense bullae at the anterior fat pads of the distal phalanx of digits 2 through 5 of the right hand and digit 3 of the left hand (Figures 1 and 2). A presumptive diagnosis of blistering distal dactylitis was made. An incision and drainage (I&D) yielded purulent fluid. A gram stain and bacterial culture were not done due to the patient’s financial limitations. The patient was prescribed oral cephalexin 500 mg twice a day for 10 days. At the follow-up appointment 10 days later, the bullae were no longer present (Figure 3). Given the clinical response to cephalexin, the diagnosis of blistering distal dactylitis was confirmed.

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Figure 1.

Tense bullae at the anterior fat pads of the distal phalanx of digits 2 through 5 of the right hand.

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Figure 2.

Tense bulla at the anterior fat pad of the distal phalanx of digit 3 of the left hand.

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Figure 3.

Right hand with resolved bullae at the 10-day follow-up visit.

Discussion

Blistering distal dactylitis is a localised infection of the anterior pad of the distal phalanx of the digits. Less common locations of infection include the proximal or lateral nail folds, palmar or dorsal hand, toes, and feet. ¹ Children are most commonly affected, but cases in adults are occasionally reported as well. ² Blistering distal dactylitis occurs in both immunocompetent and immunocompromised patients. Of note, our patient was not immunocompromised.

Blistering distal dactylitis should be in the differential diagnosis for an adult presenting with bullae at the fingertips. The most common etiologic pathogen is group A beta-hemolytic streptococci and rarely Staphylococcus aureus. Multiple bullae tend to occur more commonly with S. aureus infection. ³ Of note, there has been a recent report of methicillin-resistant S. aureus causing blistering distal dactylitis. ⁴ It is proposed that infection of the skin is preceded by trauma, such as insect bites, abrasions, or burns. Our patient did not recall trauma to the affected digits. Autoinoculation of the digits from nose picking is proposed to play a role in causing blistering distal dactylitis. ⁵

Blistering distal dactylitis presents as tense, tender, oval bullae that are filled with thin, seropurulent fluid. These bullae eventually progress to bullae with central erosions or simple erosions with adherent layers of skin. ¹ The differential diagnosis for this presentation is herpetic whitlow, epidermolysis bullosa, bullous impetigo, and friction blisters.^6,7 However, the vesicles of bullous impetigo are typically more superficial than those of blistering distal dactylitis. Friction blisters can be ruled out if there is no history of friction at the area (ie, history of new shoes). Finally, clinical response to antibiotics makes herpetic whitlow unlikely. ⁵ Interestingly, it has been suggested that blistering distal dactylitis and herpetic whitlow might coexist at the distal phalynx. ⁶ Blistering distal dactylitis is primarily a clinical diagnosis, but a confirmatory bacterial culture or gram stain can be performed. Management consists of I&D of the bullae as well as beta-lactam antibiotic therapy. ²