Discussion

Final Diagnosis

Our patient with a history of Down syndrome and autism had a diagnosis of crusted scabies (CS) with bacteremia caused by methicillin-sensitive Staphylococcal aureus (MSSA) and _Serratia marcescen_s. A child with CS has an increased risk of secondary bacterial infections that can lead to bacteremia and sepsis. 1 Serratia marcescens is a rare cause of bacteremia in children with CS. The differential diagnosis of CS included erythrodermic psoriasis, erythrodermic seborrheic dermatitis, and pemphigus foliaceus. Because the child lived in a mobile home, he could have had an allergic mold reaction or irritant contact dermatitis due to formaldehyde. Mobile homes are prone to mold due to high moisture and lack of ventilation. Mobile homes also have formaldehyde-treated plywood and adhesives that can cause irritant contact dermatitis. 2

Hospital Course

Upon admission to hospital on the pediatric floor, he was non-toxic appearing, alert but had a temperature of 101.4°F and had erythematous papules and crusted lesions over 80% of his body (Figures 1-3). Shortly after admission, blood cultures were reported to be positive for MSSA and the patient was started on doxycycline, and nafcillin for the MSSA. The repeat blood culture 4 days after admission was positive for _S. marcescen_s, so that the antibiotics were switched to vancomycin and cefepime, but then changed to nafcillin and ceftriaxone as recommended by pediatric infectious disease physicians. Ultimately, the blood cultures were negative, and he was prescribed 10 more days of oral levofloxacin on discharge. The patient’s blood work revealed a slightly elevated white blood cell of 13.53 (normal 4.5-13.50) and absolute neutrophil count of 11.5 (normal 15.0-10.3). His inflammatory markers were elevated, C-reactive protein 3.5 (normal <0.08), procalcitonin 0.80 (normal <0.07) yet erythrocyte sedimentation rate normal at 20 (normal 2-30). There were no laboratory results significant for an immune or chronic granulomatous disease.

Figures 1, 2, 3.: Before admitted to hospital.

Dermatology was consulted on hospital day 1, with a 4 mm biopsy performed from his neck and direct immunofluorescence obtained. Mineral oil scraping was performed and showed scabies mites, eggs, and feces. The patient was started on oral ivermectin to treat the scabies. In addition, he was also started on triamcinolone ointment and IV Benadryl for symptom control. The treatment with permethrin ointment was started once the patient’s skin condition improved to the point that it was not painful to apply (Figures 4 and 5). He was seen again at outpatient dermatology clinic, who noted dramatic improvement of symptoms, and prescribed another round of permethrin cream to the patient and family members.

Figure 4,5.: After treatment.