Blistering Dactylitis

Blistering Dactylitis

Primary Care Visit Report   

A 37-year-old female with no past medical history presented with redness and peeling skin on bilateral hands and fingers after sustaining a dog bite 2 weeks prior. The patient was bitten on both hands when she jumped in to separate a dog fight. The patient initially went to an emergency room and was given  tetanus   and  rabies vaccines. Three days later, her fingers were swelling so she went back to the ER and was admitted for 3 days of IV  antibiotics   (vancomycin and ampicillin/sulbactam) and was discharged on amoxicillin/clavulanate and doxycycline, which she was taking at the time of this visit. 

 While the pain and stiffness in her fingers had improved somewhat, the patient remained concerned because she noticed the night prior that certain areas had become “red and bumpy” and about 4 h later, the skin on her fingers began to peel. The patient had no fever or chills, and felt fine otherwise. 

 At the time of this visit, the patient was status post three rabies vaccinations on Day 0, Day 3 and Day 7 and was due for the fourth vaccine, though she found out from its owner that the dog who bit her was up to date on its rabies  vaccinations. 

 Vitals were normal. On exam, on bilateral hands, there were multiple erythematous lesions with erythematous bases at the sites of the  dog bites  . There was peeling on the periphery of many of the lesions, and many were indurated and tender to palpation. 

Specifi cally, the right hand pinky finger had erythema and tenderness to palpation spanning the full circumference of her fi nger (dorsal and ventral aspect) at the distalinterphalangeal joint and extending proximally with limited active range of motion (but full passive range of motion) at the distalinterphalangeal joint. At the periphery of the erythema, the skin was peeling. The left thumb had a 1.5 cm × 1.0 cm erythematous lesion with peeling skin at the periphery, with some induration and tenderness to palpation. The left fourth finger had a 3.0 cm × 1.5 cm erythematous, tender and indurated  lesion   with peeling at the periphery at the  proximal interphalangeal joint. She had limited active range of motion at this joint (normal passive range of motion). No warmth on any of the lesions. Peripheral pulses were normal. 

 Since the patient was already on  antibiotics   yet continued to have further worsening of pain and developed new areas of erythema and peeling, I was concerned about an abscess and referred her immediately to a hand surgeon for further evaluation. The hand surgeon examined her and was not concerned for an abscess but did recom-mend her for physical therapy.  

    Discussion from Dermatology Clinic 

     Differential Dx   

  Blistering dactylitis  

  Epidermolysis bullosa simplex, localized type

  Bullous impetigo       

Favored Dx   

The open lesions following  dog bites   most likely contracted a  bacterial infection ,  resulting in blistering dactylitis.  


Blistering dactylitis is a condition indicative of a superfi cial infection caused by  β-hemolytic streptococcal bacteria  , or by   Staphylococcus aureus   , both of which are commonly found in  dog   saliva.  Animal bites      are common, with over one million animal bites occurring annually [ 1 ]. It is estimated that half of all Americans will experience a mammalian bite dur-ing their lifetime, and  dog bites   account for the majority of reported bites (80–90 %) although the infection rates are low (2–20 % of bites) [ 2 ]. Children are more likely to be bitten than adults, and are more likely to experience injuries to the neck and face versus adults who are more commonly bitten on the upper extremities. Bites on the hand are the most likely to develop infections [ 3 ].  


Patients in the acute blistering phase of blistering dactylitis present with superfi cial, tender blisters over the fat pads of the palmar aspects of the fi ngertips. Fingers may be erythematous and swollen, and blisters can ooze. The acute blistering phase may be very short-lived, and patients may not notice  bullae  , especially if they are small or burst soon after onset. Lesions tend to be asymptomatic; however, some patients may complain of pain and tenderness in the area, and they may be febrile.  


Obtain a bacterial culture of the blister fl uid. Cultures should rule out  MRSA  infections, which are unlikely but can occur after  dog bites  .  


Blisters can be incised and drained [ 4 ], and the wounds should be irrigated.  Rabies   and  tetanus   vaccines should be administered, if indicated. The patient should start a course of prophylactic  antibiotics  , the type of which should be determined by bacteri-ology [ 1 ]. Penicillin or ampicillin are effective against many components of dogs’ oral fl ora and doxycycline provides a good alternative in children older than 8 years [ 1 ]. The combination of amoxicillin and clavulanic acid has demonstrated effi cacy in treating  dog bites      as well [ 1 ]. If cultures reveal  MRSA  , an appropriate substitute anti-biotic such as trimethoprim/ sulfamethoxazole or doxycycline should be initiated.  


 Patients should follow up at the end of their antibiotic course to ensure the infection has cleared. Further treatment may not be necessary, unless patients complain their symptoms have not resolved.   

    Questions for the Dermatologist 

–  What do I need to be concerned about when it comes to dog (or other animal)


 The three factors contributing to potential infection are the biting animal’s oral fl ora, the bite recipient’s skin fl ora, and environmental organisms.  Rabies   would be high on the list of concerns.  Dog bites   themselves would not cause  tetanus  , but breaks in skin following the bite increase the risk of exposure to  C. tetani . Dogs’ saliva can contain  Pasteurella ,   Staphylococcus   , and   Streptococcus  species  , and, rarely, poten-tially fatal   Capnocytophaga canimorsus    [ 5 ]. Bacterial culturing should be part of the general workup. This is particularly important in  animal bites   with open wounds because bacteria can easily enter the wound. If no culture is taken and the prescribed antibiotic is not working, it will be less obvious which antibiotic to prescribe. 

–  Does the peeling skin signify normal healing? Or is it something to be concerned about?  

 The toxins produced by bacteria cause exfoliative dermatitis. The most reassuring sign is that normal skin is repopulating underneath the peeling skin. That is a sign of recovery. 

Two weeks after a dog bite is there anything else I should be worried about beyond the actual bite?

Ensure any tetanus concerns have been addressed, and find out if the biting dog’s rabies vaccinations are current. Otherwise, the patient should be managed supportively.

– In this case, the peeling did not occur until 2 weeks after the dog bites and after she has already been on 2 weeks of antibiotics . Is this common? Does this signify a super-infection from the initial dog bite, or just a new phase of the initial infection?

 Blisters that are seen in infectious blistering conditions are very superficial and rupture quite easily. It is possible that following  bacterial infection  , the patient briefl y formed superfi cial blisters that collapsed and later began to peel. The patient may not have experienced a specifi c bullous phase; however, at some point the  blisters were probably unroofed, and as the skin dried out it began to fall off and peel. Rather than signifying a super-infection, the peeling skin is more likely part of the initial infection.     


       1.   Brook I. Management of human and animal bite wound infection: an overview. Curr Infect Dis Rep. 2009;11(5):389–95.

    2.   Griego RD, Rosen T, Orengo IF, Wolf JE. Dog, cat, and human bites: a review. J Am Acad Dermatol. 1995;33(6):1019–29.

    3.   Oehler RL, Velez AP, Mizrachi M, Lamarche J, Gompf S. Bite-related and septic syndromes caused by cats and dogs. Lancet Infect Dis. 2009;9(7):439–47.

    4.   McCray MK, Esterly NB. Blistering distal dactylitis. J Am Acad Dermatol. 1981;5(5):592–4.

    5.   Thomas N, Brook I. Animal bite-associated infections. Expert Rev Anti Infect Ther. 2011;9(2):215–26.   

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