Challenges and limitations of teledermatology for skin and soft-tissue infections: A real-world study of an expert center

Red Leg Dilemma: Development and Validation of Clinical Decision Tools for Non-Necrotizing Bacterial Dermohypodermitis, Necrotizing Fasciitis, and Eczematous Dermatitis

BackgroundDiagnosing red legs on first presentation is challenging. There exists a lack of robustly developed and validated diagnostic red leg tools in clinical practice. Physicians fear missing cases of infectious red legs and treat many patients unnecessarily with antibiotics.ObjectiveDevelop and validate easy-to-use diagnostic tools applicable at bedside of patients to orient diagnosis of the commonest and most serious causes of infectious red legs (non-necrotizing bacterial dermohypodermitis (NNBDH), and necrotizing fasciitis (NF)) versus the commonest inflammatory cause (eczema).MethodsWe collected data of patients presenting to our dermatology department from January first 2012 until May 17th 2017 with a diagnosis of red leg. Three models were developed using fast frugal trees. Validation was performed in a second cohort of patients.ResultsA total of 187 patients (mean age 56, SD = 21 years, 48.1% women) were included in the development phase and 62 patients (mean age 64, SD = 19, 52% women) in the validation phase. In the validation data set, sensitivity and specificity were respectively 67% and 91% for NNBDH, 83% and 66%, for NF and 88% and 93%, for eczema.ConclusionPresentations of suspected lower-limb infections are commonly misdiagnosed, resulting in avoidable antibiotic prescription and hospitalization. We developed an easy-to-use clinical diagnostic tool applicable at the bedside of patients to help orient physicians in certain situations and avoid unnecessary initiation of antibiotics. Future work should focus on validating this tool in primary care to minimize misdiagnosis of red legs and overprescription of antibiotics.

Secondary Bacterial Infections in Patients with Atopic Dermatitis or Other Common Dermatoses

Secondary bacterial infections of common dermatoses such as atopic dermatitis, ectoparasitosis, and varicella zoster virus infections are frequent, with Staphylococcus aureus and Streptococcus pyogenes being the bacteria most involved. There are also Gram-negative infections secondary to common dermatoses such as foot dyshidrotic eczema and tinea pedis. Factors favoring secondary bacterial infections in atopic dermatitis, ectoparasitosis, and varicella zoster virus infections mainly include an epidermal barrier alteration as well as itch. Mite-bacteria interaction is also involved in scabies and some environmental factors can promote Gram-negative bacterial infections of the feet. Furthermore, the bacterial ecology of these superinfections may depend on the geographical origin of the patients, especially in ectoparasitosis. Bacterial superinfections can also have different clinical aspects depending on the underlying dermatoses. Subsequently, the choice of class, course, and duration of antibiotic treatment depends on the severity of the infection and the suspected bacteria, primarily targeting S. aureus. Prevention of these secondary bacterial infections depends first and foremost on the management of the underlying skin disorder. At the same time, educating the patient on maintaining good skin hygiene and reporting changes in the primary lesions is crucial. In the case of recurrent secondary infections, decolonization of S. aureus is deemed necessary, particularly in atopic dermatitis.