A woman with chronic subcutaneous swelling of the right foot associated with sinus tracts discharging yellow grains

Common Dermatologic Conditions in Returning Travelers

Purpose of Review

Travel medicine practitioners often are confronted with returning travelers with dermatologic disorders that could be of infectious causes or inflammatory or allergic. Some dermatologic processes are the result of exposure to insects or acquired due to environmental exposures. There is a broad range of dermatosis of infectious and non-infectious etiologies that clinicians need to consider in the differential diagnosis of dermatosis in travelers.

Recent Findings

With increasing international travel to tropical destinations, many individuals may be exposed to rickettsia (i.e., African tick bite fever, scrub typhus, or Mediterranean spotted fever), parasitic infections (i.e., cutaneous larva migrans, cutaneous leishmaniasis, African trypanosomiasis, or American trypanosomiasis), viral infections (i.e., measles or Zika virus infection), bacterial (i.e., Buruli ulcer) or ectoparasites (scabies or tungiasis), and myiasis. Cutaneous lesions provide clinical clues to the diagnosis of specific exposures during travel among returned travelers.

Summary

Dermatologic disorders represent the third most common health problem in returned travelers, after gastrointestinal and respiratory illness. Many of these conditions may pose a risk of severe complications if there is any delay in diagnosis. Therefore, clinicians caring for travelers need to become familiar with the most frequent infectious and non-infectious skin disorders in travelers.

Misdiagnosed tuberculosis being corrected as Nocardia farcinica infection by metagenomic sequencing: a case report

Background

Disseminated nocardiosis is liable to be misdiagnosed owing to the non-specific clinical manifestations and laboratory/imaging findings. Metagenomic next-generation sequencing (mNGS) is a culture-independent and rapid method for direct identification of all microorganisms in clinical specimens.

Case presentation

A 72-year-old man was admitted to our hospital on February 20, 2019 with a history of recurrent cough, expectoration, fever, and diarrhea since 1 month, and unconsciousness since 1 week. Contrast-enhanced magnetic resonance imaging of head showed multiple lesions in the bilateral cerebral hemispheres, brainstem, and cerebellar hemispheres. The presumptive diagnosis was disseminated tuberculosis, although all tests for mycobacterium were negative. However, the patient did not benefit from antituberculosis treatment. Repeat MRI showed multiple abnormal signals in the brain and progression of meningeal thickening. Cerebrospinal fluid and bronchoalveolar lavage fluid specimens were subsequently sent for PMSeq metagenomics sequencing; the results indicated Nocardia. farcinica as the predominant pathogen. The anti-TB treatment was stopped and the patient was prescribed sulphamethoxazole in combination with linezolid and meropenem for nocardiosis. He showed gradual neurological improvement and was transferred to Huashan Hospital. He was discharged from the hospital on April 19, 2019, but died of persistent diarrhea on May 26, 2019.

Conclusions

Patients with suspected nocardiosis do not always respond to conventional treatment; therefore, mNGS can facilitate diagnosis and timely treatment decision-making.

Isolated Nocardiosis, an Unrecognized Primary Immunodeficiency?

Nocardiosis is an infectious disease caused by the gram-positive bacterium Nocardia spp. Although it is commonly accepted that exposure to Nocardia is almost universal, only a small fraction of exposed individuals develop the disease, while the vast majority remain healthy. Nocardiosis has been described as an "opportunistic" disease of immunocompromised patients, suggesting that exposure to the pathogen is necessary, but a host predisposition is also required. Interestingly, increasing numbers of nocardiosis cases in individuals without any detected risk factors, i.e., without overt immunodeficiency, are being reported. Furthermore, a growing body of evidence have shown that selective susceptibility to a specific pathogen can be caused by a primary immunodeficiency (PID). This raises the question of whether an undiagnosed PID may cause nocardiosis affecting otherwise healthy individuals. This review summarizes the specific clinical and microbiological characteristics of patients with isolated nocardiosis published during the past 30 years. Furthermore, it gives an overview of the known human immune mechanisms to fend off Nocardia spp. obtained from the study of PIDs and patients under immunomodulatory therapies.

Subcutaneous mycoses in coastal Karnataka in south India

BACKGROUND

Subcutaneous mycoses are chronic, localized infections of the skin and subcutaneous tissue which occur following traumatic implantation of the etiological agent. The causative organisms are soil saprophytes of regional epidemiology with varying ability to adapt to the tissue environment and elicit disease.

OBJECTIVES

This study was conducted to evaluate the various types of subcutaneous mycoses, including actinomycotic mycetomas, in south coastal Karnataka, India.

METHODS

Between January 2005 and January 2013, a total of 25 patients were diagnosed with subcutaneous mycoses based on a detailed clinical history and presentation, histopathology, and culture of organisms.

RESULTS

Chromoblastomycosis was the infection most commonly seen (n = 16 patients, 64%), followed by mycetoma (n = 4, 16%), sporotrichosis (n = 4, 16%), and rhinoentomophthoromycosis (n = 1, 4%). The extremities were the most common site of involvement, with the lower limb being most affected (64%). Males were more commonly afflicted (64%) than females (36%). Most patients were agricultural workers, although preceding trauma was noted in only three patients. The majority of patients responded well to therapy and were disease-free on follow-up.

CONCLUSIONS

Subcutaneous mycoses are a rare group of disorders. Chromoblastomycosis is the most frequent subcutaneous fungal infection in south India. Morphologically, chromomoblastomycoses present as verrucous, ulcerative, nodular, or eczematous lesions. Clinical diagnosis is important as culture is often negative. The incidence of infection is higher among rubber tappers. It is important to clinically differentiate chromoblastomycosis from tuberculosis verrucosa cutis. Most of the subcutaneous mycoses respond well to treatment, with the exception of rhinoentomophthoromycosis, which is a rare form of deep mycosis with associated mutilation. Eumycetomas are not observed in this part of India.

Mycetoma caused by Nocardia yamanashiensis, Papua New Guinea

We report the first documented case of a mycetoma caused by Nocardia yamanashiensis after the initial description of this species. The 16S-rRNA gene sequence analysis was used to identify the novel species, which showed a similarity of 99.9% to the gene sequence of the type strain. The case showed both clinical non-response and reduced susceptibility in vitro to amoxicillin plus clavulanate, and it was treated successfully with trimethoprim-sulfamethoxazole and doxycycline. Given antibiotic resistance concerns, we suggest that antimicrobial susceptibility testing should be done for the majority of Nocardia species without well-established resistance patterns.