Pemphigus foliaceous is an autoimmune intraepidermal blistering disease with lesions occurring on the face, scalp, chest, and upper back.5 Intact blisters are not commonly seen. The vesicle roof is very thin and ruptures easily, forming broad areas of crust. Skin biopsy reveals intraepidermal bulla or acantholysis in the upper epidermis.
Pemphigus vulgaris is also an autoimmune blistering disease that affects the skin and mucous membranes. It is generally seen among patients aged >40 years.
Bullous pemphigoid is an autoimmune disorder presenting with chronic eruption of erythematous, papular, urticaria lesions often evolving into bullae. Childhood cases are rare. Biopsy of the lesions demonstrates subepidermal bulla with an infiltration of eosinophils within the dermis.5
Erythema migrans with central vesiculation must be considered given the patient’s camping trip. Recent evidence shows that erythema migrans with central redness accounts for most cases in areas endemic for Lyme disease. Only 10% of the patients with early Lyme disease show the classic bulls-eye lesion with concentric erythematous rings and central clearing. Vesiculation can occur in up to 30% of lesions.6
Staphylococcus aureus and antibiotic resistance
As many as 61% of community-acquired methicillin-resistant S aureus (MRSA) infections are initially treated only with beta-lactam antibiotics, to which they are resistant.7 Risk factors for community-acquired MRSA infection include day-care attendance, recent hospitalization, recent antibiotic use, chronic illness, and frequent health care visits.8 A growing number of cases are reported among patients without risk factors.
Community-acquired MRSA isolates are usually genetically different from nosocomial isolates, and have been relatively susceptible to non–beta-lactam antibiotics. These strains vary substantially, however, and it is important to check the susceptibility of the isolate.
Virulent new strains of S aureus are infecting children—these strains have a novel transpeptidase, which offers them a mechanism of resistance to beta-lactams different from hospital-and community-acquired types.
Awareness of the local antimicrobial susceptibility patterns of community S aureus isolates is also helpful. Oral antibiotics that have been successful include clindamycin, minocycline, doxycycline, and trimethoprim-sulfamethoxazole. Cephalexin has no therapeutic value in treating community-acquired MRSA.
Preventing disease spread in the patient and contacts
Preventive efforts should be directed at patients with recurrent episodes of MRSA skin abscesses. Metabolic and immunologic screening should be performed to rule out underlying disease processes causing increased risk for infection. In most cases these test results are normal, and patients with recurrent MRSA skin abscesses should also be empirically treated for presumed nasal carriage of MRSA.
Mupirocin ointment (Bactroban) should be applied to the nares twice daily for 5 days in an effort to prevent recurrent self-inoculation and lateral transmission of MRSA.
Patients and families should also be instructed in hygienic measures such as daily changing of underwear and personal use only of towels, washcloths, and sleepwear. Fingernails should be kept short and clean. Open insect bites or superficial skin abrasions should be kept clean and covered. Benefit from the daily use of antimicrobial soaps is controversial.