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.

Gram-Negative Toe Web Infections

Gram-negative bacterial toe web infection (GNTWI) is a common dermatologic condition affecting the interdigital spaces. The clinical presentation ranges from mild erythema to exudative maceration of the web spaces that may extend to in other areas of the foot and lead to cellulitis in severe cases. Pseudomonas aeruginosa is the most commonly identified etiologic agent. Occlusive and humid environments, pre-existing dermatologic conditions, and fungal infections increase the risk of developing GNTWI. GNTWI has a broad differential diagnosis including erythrasma, tinea pedis, pitted keratolysis, eczematous dermatitis, and malignancies. Diagnosis is performed using bacterial and fungal cultures. There is a lack of a standardized treatment regimen for GNTWI. While GNTWI is fairly common, it may still be under-recognized by dermatologists due to the limited medical literature. This article presents a review of GNTWI, its clinical features, epidemiologic factors, etiologic agents, predisposing factors, diagnostic methods, and therapeutic options.

Skin manifestations of Pseudomonas aeruginosa infections

PURPOSE OF REVIEW

Pseudomonas aeruginosa is an opportunistic pathogen with considerable morbidity and mortality, particularly in vulnerable hosts. Skin manifestations are common, either representing local inoculation or secondary skin seeding following bloodstream infections. As patients with various predisposing conditions are expanding, we sought to review the most recent published evidence regarding epidemiology, risk factors and diagnosis of skin manifestations of P. aeruginosa.

RECENT FINDINGS

New data exist on epidemiology and diagnosis of skin infections; systemic infections are impacted by multidrug-resistance issues and host immune status.

SUMMARY

Green nail syndrome, toe web infection, hot tub folliculitis, hot hand-foot infection and external otitis are the most common infections originating from the skin per se. Local treatments are the cornerstone and prognosis is favorable in immunocompetent hosts. Ecthyma gangrenosum and P. aeruginosa subcutaneous nodules are usually associated with bloodstream infections and occur primarily in immunocompromised hosts. Necrotizing skin and soft tissue infections occur in diabetic, alcoholic and immunocompromised patients; management requires a multidisciplinary team with surgical approach. Burn wound infections may also be challenging, requiring a specialized team. In all the four latter types of P. aeruginosa skin infections portending significant morbidity and mortality, systemic antibiotics are an integral part of the treatment.

Predictors for readmission due to cellulitis among Japanese patients

Cellulitis is an infection of the soft tissues of the skin. Some patients are hospitalized multiple times; lymphedema, chronic venous insufficiency, peripheral circulatory disturbance, and deep vein thrombosis are said to be risk factors for multiple admissions. Conversely, in Japan, elderly women and undernourished elderly have been reported to be at risk of multiple hospitalizations, suggesting a different patient background from that reported overseas. We investigated the characteristics of readmission cases for patients hospitalized for cellulitis in Japan. We retrospectively examined cases of cellulitis and erysipelas admitted between April 1, 2005 and March 31, 2018. Patients with cellulitis or erysipelas at multiple sites and those with osteomyelitis, pressure ulcer infection, and necrotizing fasciitis were excluded. In terms of recurrence, only hospitalizations for recurrence at the same site were considered. Patients with multiple hospitalizations had significantly lower blood albumin levels than those hospitalized only once. Furthermore, the rates of lymphedema, hypertension, and hyperlipidemia were significantly higher in patients hospitalized multiple times. Other laboratory and clinical factors were not statistically significant. Therefore, hypoalbuminemia with or without liver dysfunction, lymphedema, hypertension, and hyperlipidemia were suggested as risk factors for cellulitis recurrence. However, chronic venous insufficiency, peripheral circulatory disturbance, and deep vein thrombosis did not seem to be risk factors in Japanese cases. Japanese cases had a low body mass index (approximately 25 kg/m²), suggesting that the patient background may be different from that in existing reports. This suggests that the risk factors in Japanese cases may be different from those reported in other countries.