Juvenile spring eruption: an outbreak report and systematic review of the literature

Juvenile spring eruption of the helices of the ears is a distinctive sun-induced condition appearing on the light-exposed skin of the ears, typically in boys and young men in early spring.

Disseminated Mycobacterium marinum infection with extensive cutaneous eruption and bacteremia in an immunocompromised patient

Mycobacterium marinum can cause fish tank granuloma (or swimming pool or aquarium granuloma) in immunocompetent patients. Dissemination of Mycobacterium marinum-infection is a rare condition which occurs mainly in immunocompromised patients and can be life-threatening. We report the case of an 87-year-old woman who was treated with oral corticosteroids for polymyalgia rheumatica for many years and developed erythema nodosum-like lesions on the right forearm and arthritis of the right wrist. By increasing the steroid dosage and adding methotrexate only short-term remission was achieved. Seven months later painful erythematous nodules occurred on all extremities which became necrotic, ulcerative and suppurative. Ziehl-Neelsen staining revealed acid-fast bacilli and Mycobacterium marinum was cultured from skin biopsies, blood, and urine. The critically ill patient was treated with clarithromycin and ethambutol resulting in a dramatic improvement of the general condition. After four months, doxycycline had to be added because of new skin lesions. This case illustrates the impact of Mycobacterium marinum infection in immunocompromised patients.

Modeling the stratospheric warming following the Mt. Pinatubo eruption: uncertainties in aerosol extinctions

In terms of atmospheric impact, the volcanic eruption of Mt. Pinatubo (1991) is the best characterized large eruption on record. We investigate here the model-derived stratospheric warming following the Pinatubo eruption as derived from SAGE II extinction data including recent improvements in the processing algorithm. This method, termed SAGE_4λ, makes use of the four wavelengths (385, 452, 525 and 1024 nm) of the SAGE II data when available, and uses a data-filling procedure in the opacity-induced "gap" regions. Using SAGE_4λ, we derived aerosol size distributions that properly reproduce extinction coefficients also at much longer wavelengths. This provides a good basis for calculating the absorption of terrestrial infrared radiation and the resulting stratospheric heating. However, we also show that the use of this data set in a global chemistry–climate model (CCM) still leads to stronger aerosol-induced stratospheric heating than observed, with temperatures partly even higher than the already too high values found by many models in recent general circulation model (GCM) and CCM intercomparisons. This suggests that the overestimation of the stratospheric warming after the Pinatubo eruption may not be ascribed to an insufficient observational database but instead to using outdated data sets, to deficiencies in the implementation of the forcing data, or to radiative or dynamical model artifacts. Conversely, the SAGE_4λ approach reduces the infrared absorption in the tropical tropopause region, resulting in a significantly better agreement with the post-volcanic temperature record at these altitudes.

Tooth eruption: altered gene expression in the dental follicle of patients with cleidocranial dysplasia

OBJECTIVES The dental follicle plays an important role in tooth eruption by providing key regulators of osteogenesis and bone resorption. Patients with cleidocranial dysplasia (CCD) exhibit delayed tooth eruption in combination with increased bone density in the maxilla and mandible, suggesting disturbances in bone remodeling. The aim of this study was to determine the expression of genes relevant for tooth eruption and bone remodeling in the dental follicles of patients with CCD and normal subjects. MATERIAL AND METHODS Thirteen dental follicles were isolated from five unrelated patients with CCD, and fourteen dental follicles were obtained from 10 healthy individuals. All teeth were in the intraosseous phase of eruption. The expression of RANK, RANKL, OPG, and CSF-1 was determined by quantitative RT-PCR. RESULTS In patients with CCD, the mRNA levels of RANK, OPG, and CSF-1 were significantly elevated compared with the control group. Accordingly, the ratios of RANKL/OPG and RANKL/RANK mRNAs were significantly decreased in patients with CCD. CONCLUSION The observed alterations in the expression and ratios of the aforementioned factors in the dental follicle of CCD individuals suggest a disturbed paracrine signaling for bone remodeling that could be responsible for the impaired tooth eruption seen in these patients.

Distinct lake level lowstand in Lake Prespa (SE Europe) at the time of the 74 (75) ka Toba eruption

Abstract. The 74 (75) ka Toba eruption in Sumatra, Indonesia, is considered to be one of the largest volcanic events during the Quaternary. Tephra from the Toba eruption has been found in many terrestrial and marine sedimentary deposits, and acidity peaks related to the eruption have been used to synchronize ice core records from Greenland and Antarctica. Seismic profiles and sedimentological data from Lake Prespa on the Balkan Peninsula, SE Europe, indicate a lake level lowstand at 73.6±7.7 ka based on ESR dating of shells. Tephrostratigraphy, radiocarbon dating and tuning of the total organic carbon content with the NGRIP isotope record, corroborate that the lake level lowstand was a short-term event superimposed on the general cooling trend at the end of MIS 5, most likely at the onset of the Greenland Stadial GS- 20. Acknowledging that tectonic events or karst processes could have triggered this lake level lowstand, the chronological correspondence between the lowstand and the Toba eruption is intriguing. Therefore a Toba-driven short-term shift to aridity in the Balkan region, leading to lake level changes and triggering spatial expansion events in one of the lake’s most abundant benthic species, the carino mussel Dreissena presbensis, cannot be excluded.

Direct linking of Greenland and Antarctic ice cores at the Toba eruption (74 ka BP)

The Toba eruption that occurred some 74 ka ago in Sumatra, Indonesia, is among the largest volcanic events on Earth over the last 2 million years. Tephra from this eruption has been spread over vast areas in Asia, where it constitutes a major time marker close to the Marine Isotope Stage 4/5 boundary. As yet, no tephra associated with Toba has been identified in Greenland or Antarctic ice cores. Based on new accurate dating of Toba tephra and on accurately dated European stalagmites, the Toba event is known to occur between the onsets of Greenland interstadials (GI) 19 and 20. Furthermore, the existing linking of Greenland and Antarctic ice cores by gas records and by the bipolar seesaw hypothesis suggests that the Antarctic counterpart is situated between Antarctic Isotope Maxima (AIM) 19 and 20. In this work we suggest a direct synchronization of Greenland (NGRIP) and Antarctic (EDML) ice cores at the Toba eruption based on matching of a pattern of bipolar volcanic spikes. Annual layer counting between volcanic spikes in both cores allows for a unique match. We first demonstrate this bipolar matching technique at the already synchronized Laschamp geomagnetic excursion (41 ka BP) before we apply it to the suggested Toba interval. The Toba synchronization pattern covers some 2000 yr in GI-20 and AIM-19/20 and includes nine acidity peaks that are recognized in both ice cores. The suggested bipolar Toba synchronization has decadal precision. It thus allows a determination of the exact phasing of inter-hemispheric climate in a time interval of poorly constrained ice core records, and it allows for a discussion of the climatic impact of the Toba eruption in a global perspective. The bipolar linking gives no support for a long-term global cooling caused by the Toba eruption as Antarctica experiences a major warming shortly after the event. Furthermore, our bipolar match provides a way to place palaeo-environmental records other than ice cores into a precise climatic context.

Geochemical variability in distal and proximal glass from the Youngest Toba Tuff eruption

The Youngest Toba Tuff (YTT, erupted ca. 74 ka ago) is a distinctive and widespread tephra marker across south and southeast Asia. The climatic, human and environmental consequences of the YTT eruption are widely debated. Although a considerable body of geochemical data is available for this unit, there has not been a systematic study of the variability of the ash geochemistry. Intrinsic (magmatic) and extrinsic (post-depositional) chemical variations bring fundamental information regarding the petrogenesis of the magma, the distribution of the tephra and the interaction between the ash and the receiving environment. Considering the importance of the geochemistry of the YTT for stratigraphic correlations and eruptive models, it is central to the YTT debate to quantify and interpret such variations. Here we collate all published geochemical data on the YTT glass, including analyses from 68 sites described in the literature and three new samples. Two principal sources of chemical variation are investigated: (i) compositional zonation of the magma reservoir, and (ii) post-depositional alteration. Post-depositional leaching is responsible for up to ca. 11% differences in Na2O/K2O and ca. 1% differences in SiO2/Al2O3 ratios in YTT glass from marine sites. Continental tephra are 2% higher in Na2O/K2O and 3% higher in SiO2/Al2O3 respect to the marine tephra. We interpret such post-depositional glass alteration as related to seawater induced alkali migration in marine environments, or to site-specific water pH. Crystal fractionation and consequential magmatic differentiation, which produced order-of-magnitude variations in trace element concentrations reported in the literature, also produced major element differences in the YTT glass. FeO/Al2O3 ratios vary by about 50 %, which is analytically significant. These variations represent magmatic fractionation involving Fe-bearing phases. We also compared major element concentrations in YTT and Oldest Toba Tuff (OTT) ash samples, to identify potential compositional differences that could constrain the stratigraphic identity of the Morgaon ash (Western India); no differences between the OTT and YTT samples were observed.

Late Quaternary history of the Vakinankaratra volcanic field (central Madagascar): insights from luminescence dating of phreatomagmatic eruption deposits

The Quaternary Vakinankaratra volcanic field in the central Madagascar highlands consists of scoria cones, lava flows, tuff rings, and maars. These volcanic landforms are the result of processes triggered by intracontinental rifting and overlie Precambrian basement or Neogene volcanic rocks. Infrared-stimulated luminescence (IRSL) dating was applied to 13 samples taken from phreatomagmatic eruption deposits in the Antsirabe–Betafo region with the aim of constraining the chronology of the volcanic activity. Establishing such a chronology is important for evaluating volcanic hazards in this densely populated area. Stratigraphic correlations of eruption deposits and IRSL ages suggest at least five phreatomagmatic eruption events in Late Pleistocene times. In the Lake Andraikiba region, two such eruption layers can be clearly distinguished. The older one yields ages between 109 ± 15 and 90 ± 11 ka and is possibly related to an eruption at the Amboniloha volcanic complex to the north. The younger one gives ages between 58 ± 4 and 47 ± 7 ka and is clearly related to the phreatomagmatic eruption that formed Lake Andraikiba. IRSL ages of a similar eruption deposit directly overlying basement laterite in the vicinity of the Fizinana and Ampasamihaiky volcanic complexes yield coherent ages of 68 ± 7 and 65 ± 8 ka. These ages provide the upper age limit for the subsequently developed Iavoko, Antsifotra, and Fizinana scoria cones and their associated lava flows. Two phreatomagmatic deposits, identified near Lake Tritrivakely, yield the youngest IRSL ages in the region, with respective ages of 32 ± 3 and 19 ± 2 ka. The reported K-feldspar IRSL ages are the first recorded numerical ages of phreatomagmatic eruption deposits in Madagascar, and our results confirm the huge potential of this dating approach for reconstructing the volcanic activity of Late Pleistocene to Holocene volcanic provinces.

Gustatory dysfunction after mandibular zoster

Varicella zoster, limited to the mandibular nerve, is rare. Classical symptoms are pain, hypesthesia and vesicular eruption restricted to the third trigeminal segment (V3). Little is known on taste affection after mandibular nerve zoster. We report two cases of patients suffering from mandibular zoster associated with subjective taste disorder. In both cases, gustatory measures confirmed ipsilateral hemiageusia of the anterior two-thirds of the tongue. After 2 months, the symptoms regressed and psychophysical measures came back to normal values, whereas post-zoster neuralgia lasted for more than 1 year. Gustatory dysfunction is a possible symptom after mandibular nerve zoster. In contrast to post-zoster neuralgia, taste function seems to recover quickly.

Amicrobial pustulosis-like rash in a patient with Crohn's disease under anti-TNF-alpha blocker

Amicrobial pustulosis of the folds (APF) is a recently described entity characterized by relapsing pustular lesions predominantly involving the cutaneous flexures and scalp. This disease typically occurs in association with systemic lupus erythematosus and a variety of other autoimmune diseases. We here describe an APF-like pustular eruption predominantly affecting the scalp, face and trunk, occurring during long-term infliximab treatment for Crohn's disease. Immunohistochemical staining of skin biopsy specimens for myxovirus resistance protein A, a marker for type 1 interferon-inducible proteins, showed increased staining in the epidermis and dermal mononuclear inflammatory infiltrate. Our observation further extends the spectrum of cutaneous adverse reactions potentially related to anti-tumor necrosis factor-α, the clinical context in which APF can occur as well as its clinical presentations.

Reticulate eruptions: Part 2. Historical perspectives, morphology, terminology and classification

Reticulate eruptions of vascular origin may represent an underlying arterial, venous, microvascular or combined pathology. In the presence of arterial pathology, individual rings are centred around ascending arterial vessels that supply the corresponding area of skin within an arterial hexagon that clinically presents with a blanched centre. Confluence of multiple arterial hexagons generates a stellate (star-like) pattern. In the presence of a primary venous pathology, individual rings correspond to the underlying reticular veins forming multiple venous rings. Focal involvement of a limited number of vessels presents with a branched (racemosa) configuration while a generalized involvement forms a reticulate (net-like) pattern. 'Livedo' refers to the colour and not the pattern of the eruption. Primary livedo reticularis (Syn. cutis marmorata) is a physiological response to cold and presents with a diffuse blanchable reticulate eruption due to vasospasm of the feeding arteries and sluggish flow and hyperviscosity in the draining veins. Livedo reticularis may be secondary to underlying conditions associated with hyperviscosity of blood. Livedo racemosa is an irregular, branched eruption that is only partially-blanchable or non-blanchable and always signifies a pathological process. Retiform purpura may be primarily inflammatory with secondary haemorrhage or thrombohaemorrhagic, as seen in disseminated intravascular coagulopathy.