Persistent perpendicular pigmentation: a peculiar but specific type of persistent nevus.

Persistent nevi are commonly encountered in clinical and dermatopathology practice. Although they may mimic melanoma on clinical presentation as well as microscopic review, they behave in a benign fashion and are not associated with more aggressive behavior than the original nevus. Persistent nevi may exhibit asymmetry and irregular features that prompt concern for melanoma. However, the relative circumscription and restriction of pigment to the surgical scar provides a valuable clue to diagnosis. Some persistent nevi may have a linear pattern when they are confined to a widening scar. In this situation, the pigment spreads along the lines of skin tension (Langer lines). This unique pattern can be easily identified and should be a reassuring finding. We present a case of persistent nevus with a striking perpendicular pigmentation confined to the scar; the clinical and histologic features of persistent nevi are reviewed.

Oral involvement of cutaneous T-cell lymphoma.

Methylisothiazolinone (MI) is commonly used as a preservative in personal care products and is a frequent cause of allergic contact dermatitis. We present a patient with allergic contact dermatitis caused by MI in hair care products and discuss this allergen to bring attention to this common cause of contact dermatitis, and to highlight its frequent use in hair care products. If allergy to MI is suspected, testing should be performed to this individual preservative, as testing solely for the combination preservative, methylisothiazolinone/methylchloroisothiazolinone (Kathon CG®), may miss many cases of MI allergy.

Effects of co-occurring Wolbachia and Spiroplasma endosymbionts on the Drosophila immune response against insect pathogenic and non-pathogenic bacteria.

BACKGROUND: Symbiotic interactions between microbes and animals are common in nature. Symbiotic organisms are particularly common in insects and, in some cases, they may protect their hosts from pathogenic infections. Wolbachia and Spiroplasma endosymbionts naturally inhabit various insects including Drosophila melanogaster fruit flies. Therefore, this symbiotic association is considered an excellent model to investigate whether endosymbiotic bacteria participate in host immune processes against certain pathogens. Here we have investigated whether the presence of Wolbachia alone or together with Spiroplasma endosymbionts in D. melanogaster adult flies affects the immune response against the virulent insect pathogen Photorhabdus luminescens and against non-pathogenic Escherichia coli bacteria. RESULTS: We found that D. melanogaster flies carrying no endosymbionts, those carrying both Wolbachia and Spiroplasma, and those containing Wolbachia only had similar survival rates after infection with P. luminescens or Escherichia coli bacteria. However, flies carrying both endosymbionts or Wolbachia only contained higher numbers of E. coli cells at early time-points post infection than flies without endosymbiotic bacteria. Interestingly, flies containing Wolbachia only had lower titers of this endosymbiont upon infection with the pathogen P. luminescens than uninfected flies of the same strain. We further found that the presence of Wolbachia and Spiroplasma in D. melanogaster up-regulated certain immune-related genes upon infection with P. luminescens or E. coli bacteria, but it failed to alter the phagocytic ability of the flies toward E. coli inactive bioparticles. CONCLUSION: Our results suggest that the presence of Wolbachia and Spiroplasma in D. melanogaster can modulate immune signaling against infection by certain insect pathogenic and non-pathogenic bacteria. Results from such studies are important for understanding the molecular basis of the interactions between endosymbiotic bacteria of insects and exogenous microbes.

Isavuconazonium for the treatment of Purpureocillium lilacinum infection in a patient with pyoderma gangrenosum.

Purpureocillium lilacinum is a rare but emerging pathogen in immunocompromised patients that primarily infects the skin and subcutaneous tissue. We present a novel case of Purpureocillium lilacinum infection in a patient with pyoderma gangrenosum who was successfully treated with isavuconazonium, followed by a literature review of 13 total cases of infection with Purpureocillium lilacinum gathered from a review of the PubMed database. Previous reports have utilized voriconazole, an antifungal with significant toxic side effects. Our case highlights the importance of culture and biopsy in patients with pyoderma gangrenosum who are unresponsive to standard treatment irrespective of pathergy risk.

Endosymbiotic bacteria in insects: guardians of the immune system?

Insects have evolved obligate, mutualistic interactions with bacteria without further transmission to other eukaryotic organisms. Such long-term obligate partnerships between insects and bacteria have a profound effect on various physiological functions of the host. Here we provide an overview of the effects of endosymbiotic bacteria on the insect immune system as well as on the immune response of insects to pathogenic infections. Potential mechanisms through which endosymbionts can affect the ability of their host to resist an infection are discussed in the light of recent findings. We finally point out unresolved questions for future research and speculate how the current knowledge can be employed to design and implement measures for the effective control of agricultural insect pests and vectors of diseases.