HISTORY
Chief complaint: expanding honey-crusted lesion with vesicles and bullae on the right anterior lower leg.
A 17-year-old female patient presented via teledermatology with a 7-day history of an expanding lesion located on her right anterior lower leg below the knee. It began with an abrasion after a fall and developed tender, honey-colored crusting within 72 hours. She denies pruritus, systemic symptoms, or regional adenopathy.
* Prior treatment: none
* Prior biopsy: none
* Skin history: none
* No other significant laboratory/study findings
TELEDERMATOLOGY IMAGING READER REPORT1
There is one image provided with this teledermatology visit (Figure 1). The image shows a 12 cm x 5 cm erythematous patch on the right anterior lower leg with overlying scaling, slight honey-colored crusting, vesicles, and blistering at the borders with a superiorly placed 1-cm cloudy bullae.
IMAGE QUALITY ASSESSMENT
Fully satisfactory.
INTERPRETATION OF IMAGES
Lesion
The finding of a honey-colored crusting and blistering preceded by trauma is typical of bullous impetigo.
RECOMMENDATIONS
Skin Care Recommendations
Soak the area in warm water followed by gentle removal of the crust with a moist towel 3 times daily for 3 days.
Medication Recommendations
Apply mupirocin 2% ointment 3 times daily.
RECOMMENDED FOLLOW-UP
Refer to dermatology clinic (face-to-face) to evaluate if the lesion does not improve in the next 4 days.
CLINICAL PEARL
An erythematous patch at the site of minor trauma associated with secondary scaling, honey-colored crusting, tenderness, and vesiculation evolving into transparent flaccid bullae is typical of bullous impetigo. This highly contagious disease often presents in young children but may also indicate a high risk of HIV-1 infection in homosexual men (Donovan et al., 1992). Bullous impetigo is often because of variants of staphylococci that produce exfoliative toxin A (Al-Hammadi & Hammadi, 2008). This toxin can also lead to Staphylococcal scalded skin syndrome (SSSS) by inducing cleavage of the desmoglein-1 complex in the stratum granulosum, resulting in sloughing of the superficial layers of the epidermis (Amagai et al., 2000). Notably, the desmoglein-1 complex is also targeted by autoantibodies in pemphigus (Stanley & Amagai, 2006). SSSS often presents in adults with renal disease or newborns who lack the renal capacity to excrete the toxin (Handler & Schwartz, 2014). This toxin is spread hematogenously in SSSS but is localized to areas of infection in bullous impetigo (Hirschmann, 2002).
The differential diagnosis includes allergic contact dermatitis, but this condition is primarily associated with pruritus rather than the tenderness seen in this patient. Management of bullous impetigo often involves topical antibiotics, such as topical mupirocin or topical retapamulin. In patients with numerous bullous impetigo lesions, oral antibiotics such as dicloxacillin or cephalexin should be considered. Antibiotic therapy typically leads to a rapid improvement in symptoms. Patients should be encouraged to practice rigorous handwashing to reduce the risk of transmission.
REFERENCES