African dust-laden atmospheric conditions activate the trigeminovascular system

Migraine, Allergy, and Histamine: Is There a Link?

The relationship between migraines and allergies is controversial. Though they are epidemiologically linked, the underlying pathophysiological connection between them remains unclear. Migraines and allergic disorders have various underlying genetic and biological causes. As per the literature, these conditions are epidemiologically linked, and some common pathophysiological pathways have been hypothesized. The histaminergic system may be the clue to understanding the correlation among these diseases. As a neurotransmitter in the central nervous system with a vasodilatory effect, histamine has a well-documented influence on the allergic response and could be involved in the pathophysiology of migraines. Histamine may influence hypothalamic activity, which may play a major role in migraines or may simply influence their severity. In both cases, antihistamine drugs could prove useful. This review examines whether the histaminergic system, particularly H3 and H4 receptors, may provide a mechanistic link between the pathophysiology of migraines and allergic disorders, two common and debilitating conditions. Identifying their connection could help identify novel therapeutic strategies.

Co-occurrence of migraine and atopy in children and adolescents: myth or a casual relationship?

PURPOSE OF REVIEW

To clarify the causal relationship between migraine and atopic disorders in children and adolescents.

RECENT FINDINGS

Migraine headache and atopic disorders including asthma are both common functional syndromes of childhood in which nature of the relationship is still debated. Attacks may induce in both disorders upon exposure to potential triggers in genetically susceptible individuals. Clinical phenotype manifests by temporary dysfunction of target tissue mediated by inflammation triggered by specific agents. Clinical features also change after puberty because of the partial effect of female sex hormones on the process. Appropriate definition of the syndrome and differentiating from other disorders are necessary not only for correct diagnosis, but also for planning of management strategies in children. Allergic rhinosinusitis needs to be differentiated from migraine even in experienced clinics. Questioning the presence of cranial autonomic symptoms is important clue in the differential diagnosis. Atopic disorder screening is particularly required in the diagnosis of migraine in childhood and adolescents. The link between both disorders of childhood seems to be far from a coincidence and some common inflammatory mechanisms are shared.

SUMMARY

On the basis of clinical features, laboratory findings and some practical clues in children, accurate diagnosis of migraine and atopic disorders are very critical for physicians, pediatricians and algologists.

Saharan dust, particulate matter and cause-specific mortality: a case-crossover study in Barcelona (Spain)

BACKGROUND

Studies measuring health effects of Saharan dust based on large particulate matter (PM) fraction groups may be masking some effects. Long distant transport reduces the amount of heavier and larger particles in the Saharan air masses increasing the relative contribution of smaller particles that may be more innocuous. This study investigates the association between different PM fractions and daily mortality during Saharan and non-Saharan days in Barcelona, Spain.

METHODS

We collected daily PM(1), PM(2.5-1) and PM(10-2.5) fractions, and cause-specific mortality (cardiovascular, respiratory and cerebrovascular) between March 2003 and December 2007. Changes of effects between Saharan and non-Saharan dust days were assessed using a time-stratified case-crossover design.

RESULTS

During non-Saharan dust days we found statistically significant (p<0.05) effects of PM(10-2.5) for cardiovascular (odds ratio for increase of an interquartile range, OR=1.033, 95% confidence interval: 1.006-1.060) and respiratory mortality (OR=1.044, 95% CI: 1.001-1.089). During Saharan dust days strongest cardiovascular effects were found for the same fraction (OR=1.085, 95% CI: 1.017-1.158) with an indication of effect modification (p=0.111). Effects of PM(2.5-1) during Saharan dust days were about the double than in non-dust days for cardiovascular and respiratory mortality, but these differences were not statistically significant.

CONCLUSION

Our results using independent fractions of PMs provide further evidence that the effects of short-term exposure to PM during Saharan dust days are associated with both cardiovascular and respiratory mortality. A better understanding of which of the different PM size fractions brought by Saharan dust is more likely to accelerate adverse effects may help better understand mechanisms of toxicity.

Ambient Sulphur Dioxide and Female ED Visits for Migraine

Ambient sulphur dioxide (SO(2)) concentrations may affect the number of female emergency department (ED) visits for migraine. ED visits diagnosed as migraine among females in two cities in Canada, Toronto (N = 704) and Ottawa (N = 3, 358), were analyzed. In the study case-crossover design was used. Conditional logistic regression was realized to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) relative to an increase in an interquartile range (IQR, in Toronto IQR = 2.9 ppb, in Ottawa IQR = 3.9 ppb) of sulphur dioxide. In the constructed conditional logistic regression models, temperature and relative humidity were adjusted in the form of natural splines. In Toronto positive and statistically significant associations of sulphur dioxide with migraine ED visits were obtained: all ages, OR = 1.04 (95% CI: 1.00, 1.08); age group [15, 50], OR = 1.05 (95% CI: 1.01, 1.09). In Ottawa positive correlations were observed: all ages, OR = 1.05 (95% CI: 0.97, 1.13); age group [15, 50], OR = 1.06 (95% CI: 0.97, 1.15). The results suggest that female migraine may be affected by ambient sulphur dioxide.

Migraine and weather: a prospective diary-based analysis

AIMS

Weather is mentioned as a trigger factor by migraine patients most frequently. We examined the impact of meteorological factors and the impact of their day-to-day change on the risk of occurrence and persistence of headache and migraine and the correlation of subjective weather perception with objective weather data.

METHODS

We performed a prospective, diary-based cohort study in 238 patients suffering from migraine with or without aura. Patients had to live within 25 km of the Vienna meteorological station and were required to keep a diary for 90 days. We analysed 11 meteorological parameters and 17 synoptic weather situations. For evaluating the hazard of occurrence and persistence of migraine and headache, we performed a univariate and a stepwise multivariate Cox regression analysis. We calculated correlations between subjective weather perception and meteorological data.

RESULTS

In the uni- and multivariate analysis, a ridge of high pressure increased the risk of headache occurrence, lower mean daily wind speed increased the risk of migraine occurrence and a day-to-day change of daily sunshine duration increased the risk of migraine occurrence. A day-to-day change of the daily minimum temperature decreased the risk of migraine persistence. After correction for multiple testing, none of these findings remained statistically significant. Subjective weather perceptions did not correlate with the occurrence or persistence of migraine or headache. Subjective perception of cold and too-cold weather and of too-warm weather correlated with daily minimum, mean and maximum temperature.

CONCLUSION

The influence of weather factors on migraine and headache is small and questionable.