Anaplasma phagocytophilum is a Gram-negative obligate intracellular bacterium that replicates in neutrophils. It is transmitted via tick-bite and causes febrile disease in humans and animals. Human granulocytic anaplasmosis is regarded as an emerging infectious disease in North America, Europe and Asia. However, although increasingly detected, it is still rare in Europe. Clinically apparent A. phagocytophilum infections in animals are mainly found in horses, dogs, cats, sheep and cattle. Evidence from cross-infection experiments that A. phagocytophilum isolates of distinct host origin are not uniformly infectious for heterologous hosts has led to several approaches of molecular strain characterization. Unfortunately, the results of these studies are not always easily comparable, because different gene regions and fragment lengths were investigated. Multilocus sequence typing is a widely accepted method for molecular characterization of bacteria. We here provide for the first time a universal typing method that is easily transferable between different laboratories. We validated our approach on an unprecedented large data set of almost 400 A. phagocytophilum strains from humans and animals mostly from Europe. The typability was 74% (284/383). One major clonal complex containing 177 strains was detected. However, 54% (49/90) of the sequence types were not part of a clonal complex indicating that the population structure of A. phagocytophilum is probably semiclonal. All strains from humans, dogs and horses from Europe belonged to the same clonal complex. As canine and equine granulocytic anaplasmosis occurs frequently in Europe, human granulocytic anaplasmosis is likely to be underdiagnosed in Europe. Further, wild boars and hedgehogs may serve as reservoir hosts of the disease in humans and domestic animals in Europe, because their strains belonged to the same clonal complex. In contrast, as they were only distantly related, roe deer, voles and shrews are unlikely to harbor A. phagocytophilum strains infectious for humans, domestic or farm animals.

Summary Syndromes associated with concurrent skin and joint inflammation frequently pose a therapeutic challenge for both dermatologists and rheumatologists. In part 1 of this review, we discussed psoriatic arthritis as well as the autoinflammatory disorders SAPHO syndrome, Still's disease and Behçet's disease. Part 2 will address rheumatoid arthritis, reactive arthritis, Reiter's syndrome and Lyme borreliosis. In addition, we will discuss dermatomyositis and lupus erythematosus, two common autoimmune disorders that frequently present with both cutaneous and joint involvement. For each of the aforementioned disorders, we will highlight aspects of epidemiology, pathogenesis, clinical presentation, diagnosis and treatment.

SummaryThe coincidence of skin and joint inflammation poses a challenge for both dermatologists and rheumatologists. Adequate management of such disorders requires that physicians of both specialties have sound knowledge of the other discipline. In case of suspected joint involvement, familiarity with the diagnostic options available to rheumatologists enables dermatologists to selectively refer their patients for a rheumatology consult. The objective of the present review is to familiarize the reader with the stepwise diagnostic workup performed by rheumatologists today, including laboratory tests, musculoskeletal ultrasound, X‐ray studies, and magnetic resonance imaging. Subsequently, we will discuss a number of disorders characterized by the concurrence of skin and joint inflammation, highlighting aspects of epidemiology, etiology and pathogenesis, clinical presentation, diagnosis and treatment. These disorders include psoriatic arthritis as well as autoinflammatory disorders such as SAPHO syndrome, Still's disease and Behçet's disease.

In 36 HIV seropositive patients with the clinical manifestation of AIDS and a suspected Pneumocystis carinii infection, lymphocyte subpopulations were analyzed in the peripheral blood (PBL) and compared with the results of the bronchoalveolar lavage (BAL). Of those 36 patients, 29 showed a highly abnormal CD4/CD8 ratio in both the PBL and the BAL. The clinical course of these 29 patients was unpredictable. In seven patients, however, the CD4/CD8 ratio in the BAL was normal or only slightly altered, despite a highly abnormal CD4/CD8 ratio in the PBL. Five of these seven patients improved greatly during the clinical course. The positive outcome of the clinical course was even more strongly correlated with the number of macrophages in the BAL. Twelve of the 36 patients showed normal or only slightly changed numbers of macrophages in the BAL. Eleven of these twelve patients (92%) improved rapidly during antibiotic therapy, while the clinical course was unpredictable in patients with markedly reduced macrophage counts in the BAL.

Continuous glucose monitoring (CGM) systems are increasingly implemented in patients with diabetes and other disorders with disturbed glucose homeostasis to promote good metabolic control.However, shortly after their appearance on the market, the first concerns about adverse skin reactions were raised. 1 CGM devices are usually combined with a subcutaneous catheter and a transmitter for blood glucose sensors applied to the skin by an adhesive patch for a period of 3-14 days. 2 Dermatological complications are especially common in children and adolescents using GCM devices. 3 Herman et al have recently identified isobornyl acrylate as the main culprit allergen to cause allergic contact dermatitis (ACD) in patients using the FreeStyle ® Libre device. 2 Interestingly, isobornyl acrylate was the American Contact Dermatitis Society Allergen of the Year in 2020. 4 We herein report on a girl with glycogen storage disease (GSD) type 9b who developed severe ACD to both FreeStyle ® Libre and Dexcom ® G6 devices. Our case highlights the severe consequences of sensitization for pediatric patients and the urgent need for open labeling as well as the use of less allergenic adhesives and components in medical devices.

ZusammenfassungDie Assoziation der Entzündung von Haut und Gelenken stellt Dermatologen und Rheumatologen oft vor diagnostische Herausforderungen. Um diese Krankheitsbilder adäquat managen zu können, benötigen beide Fachrichtungen solide Grundkenntnisse im jeweils anderen Fachgebiet. Bei Verdacht auf eine Gelenkbeteiligung kann die Kenntnis der zur Verfügung stehenden diagnostischen Möglichkeiten dem Dermatologen eine selektive und begründete konsiliarische Vorstellung bei einem Rheumatologen oder rheumatologischen Zentrum ermöglichen. Der vorliegende Beitrag vermittelt deshalb zunächst Grundkenntnisse der modernen rheumatologischen Stufendiagnostik. Diese umfasst neben labordiagnostischen Verfahren die Bildgebung wie den muskuloskelettalen Gelenkultraschall, Röntgen und Kernspintomografie. Anschließend werden Krankheitsbilder mit gleichzeitiger Entzündung von Haut und Gelenken besprochen: die Psoriasisarthritis und die autoinflammatorischen Syndrome SAPHO‐Syndrom, Morbus Still und Morbus Behçet. Bei jedem Krankheitsbild werden Epidemiologie, Ätiologie und Pathogenese, Klinik, Diagnostik und Grundzüge der Therapie besprochen.

Zusammenfassung Die Syndrome mit gleichzeitiger Entzündung von Haut und Gelenken stellen oft eine Herausforderung für Dermatologen und Rheumatologen dar. Im vorausgehenden ersten Teil dieser Übersicht wurden die Psoriasisarthritis und die autoinflammatorischen Erkrankungen SAPHO‐Syndrom, Morbus Still und Morbus Behçet behandelt. Hier folgen rheumatoide Arthritis, reaktive Arthritis, Morbus Reiter und Lyme‐Borreliose. Anschließend werden die Dermatomyositis und der Lupus erythematodes besprochen, häufige autoimmunologische Krankheiten, bei denen neben Haut oft auch die Gelenke betroffen sind. Jedes Krankheitsbild wird hinsichtlich Epidemiologie, Pathogenese, Klinik, Diagnostik und Therapie abgehandelt.