A winter visit to Austin or San Antonio and suddenly you feel like you have flu, without the flu? Locals call it cedar fever, and it comes from mountain cedar, a juniper that pollinates in midwinter. Our test checks IgE to mountain cedar pollen as part of 300 allergens and allergen components, next to cypress and Japanese cedar.
Mountain cedar is the local name for Ashe juniper (Juniperus ashei), a dense evergreen in the cypress family. It covers huge areas of central Texas and releases pollen in midwinter, often in visible clouds after a cold front passes through.
Its main allergen, Jun a 1, is a pectate lyase. It closely resembles Cup a 1 in cypress and Cry j 1 in Japanese cedar, which is why sensitisation tends to run across the whole family.
Ashe juniper does not grow wild in Finland, Ireland, the Netherlands or Germany, so mountain cedar pollen itself is a traveller's issue. If you spend December or January in Texas, you land right in the middle of its season.
Its relatives are closer to home. Common juniper grows wild in Finland and parts of Ireland, and cypress-family hedges are planted across northern Europe, though both release far less pollen than Texas juniper woodland. In southern Europe, cypress is the big winter pollen. Because the family shares its main allergen, a mountain cedar result can reflect sensitisation that started with cypress.
Despite the name, cedar fever does not usually cause a real fever. People describe a heavy, flu-like feeling: a streaming or blocked nose, sneezing, itchy eyes, a scratchy throat and tiredness.
Mountain cedar remains one of the main causes of winter hay fever in the south-central US. Symptoms tend to spike on dry, windy days after a cold front.
From a finger-prick sample, the lab measures IgE to a whole mountain cedar pollen extract as part of 300 allergens and allergen components. Italian cypress, Arizona cypress (Cup a 1) and Japanese cedar (Cry j 1) are on the same report, so you see the cypress family together.
A positive result means your blood shows IgE to mountain cedar pollen. That is sensitisation, not a diagnosis. Each value gets a class from Negative to Very high, to discuss with a doctor.
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One finger-prick sample checks IgE to 300 allergens and allergen components, from birch and peanut to cat and house dust mite. Post it to the lab, and about 5 days after it arrives you get a value for every one. Our plain-English guide shows you how to read them. €399 in total, €1.33 per allergen.
Cedar fever is the Texan name for hay fever caused by mountain cedar (Ashe juniper) pollen in winter. Despite the name it rarely causes a real fever. People describe sneezing, a blocked nose, itchy eyes and a flu-like tiredness.
In central Texas, mountain cedar usually starts in mid-December, peaks in mid-January and tails off in February. Counts jump after cold fronts pass through.
Yes. Mountain cedar is Ashe juniper, Juniperus ashei. It is a juniper in the cypress family, not a true cedar. Its main allergen resembles those of cypress and Japanese cedar.
Because the cypress family shares its main allergen. IgE made against cypress or juniper pollen in Europe can recognise mountain cedar too. Your cypress and Japanese cedar results on the same report help a doctor see the pattern.
