Juniper Pollen Allergy: Understanding Cedar Fever and the Winter Pollen Nobody Expects

Cedar fever season in Central Texas runs from mid-December through February, with peak pollen release typically occurring in January. This winter timing is one of the most counterintuitive aspects of mountain cedar allergy — most US pollen calendars show essentially no tree pollen in December, but Austin and San Antonio routinely record cedar counts exceeding 10,000 to 20,000 grains per cubic meter during January cold fronts. In other regions, western juniper and eastern red cedar extend the Cupressaceae season from January through April. Check your local NAB station for daily count updates starting in early December if you live in cedar country.

This is the hallmark of cedar fever — intense systemic inflammation from Jun a 1 exposure that produces malaise, fatigue, headache, and profound rhinorrhea without an actual elevated body temperature. The systemic symptoms result from widespread mast-cell activation and the release of leukotrienes, cytokines, and prostaglandins into the bloodstream. These mediators trigger the hypothalamic-pituitary axis in ways that mimic flu symptoms without activating the fever response. A normal thermometer reading in December or January in Central Texas with severe rhinorrhea is a classic cedar-fever presentation, not influenza.

Yes, though mountain cedar (Juniperus ashei) is concentrated in Central Texas, other juniper and cypress species produce clinically meaningful pollen across a much wider geographic area. Western juniper (J. occidentalis) causes cedar-fever-type symptoms in Oregon, Washington, Nevada, Colorado, New Mexico, and Arizona from January through March. Eastern red cedar (J. virginiana) pollinating February through April affects patients along the East Coast from Virginia to the Carolinas. Cross-reactivity within the Cupressaceae family means patients sensitized to Texas mountain cedar will also react to these regional juniper and cypress species.

Yes. Subcutaneous immunotherapy with mountain cedar extract is among the most well-established regional allergy treatments in North America. Texas allergists have practiced cedar SCIT for decades, and clinical experience consistently demonstrates significant reduction in cedar-season symptom severity and rescue medication use over 3 to 5 year treatment courses. Most patients notice improvement within their first treated cedar season. The treatment requires weekly clinic visits during the 6 to 12 month buildup phase, then monthly maintenance injections. A board-certified allergist should design and supervise the program.

No FDA-approved sublingual immunotherapy tablet for mountain cedar or any Cupressaceae pollen exists in the United States as of June 2026. Japan has approved Cedacure for Japanese cedar (Cryptomeria japonica), but this product has not been filed with the FDA and is not available in the US. US patients can access cedar SLIT through providers who formulate custom under-the-tongue drops using standard SCIT mountain cedar extract — this is off-label but mechanistically supported by the Japanese cedar SLIT evidence. The Grastek and Oralair SLIT tablets (grass) are FDA-approved but do not cover any Cupressaceae species.

No. Oral allergy syndrome (OAS) to raw apples, cherries, and hazelnuts is driven by birch Bet v 1, a PR-10 protein. Jun a 1, the major juniper allergen, is a pectate lyase — an entirely different protein family with no meaningful cross-reactivity with the PR-10 family of food allergens. Patients sensitized to mountain cedar through juniper exposure do not develop PR-10 OAS. If you have both spring rhinitis and OAS to raw apples, you likely have concurrent birch sensitization rather than juniper allergy causing your OAS. Component testing can clarify which pollen is driving each symptom.

Juniper (Juniperus), cedar (commonly referring to mountain cedar, which is biologically a juniper species, Juniperus ashei), and cypress (Cupressus) all belong to the Cupressaceae family and share Jun a 1-equivalent pectate lyase allergens. The common names are used interchangeably and confusingly in the American Southwest and Texas. Mountain cedar is Juniperus ashei — a juniper, not a true cedar (true cedars are Cedrus, a different genus). All Cupressaceae species are essentially the same immunological allergen for sensitized patients. If you react to mountain cedar in Texas, you will likely react to Arizona cypress, Italian cypress, and western juniper as well.

Because mountain cedar (Juniperus ashei) pollinates from mid-December through February — months before spring tree pollen season begins in most of the country. This makes Texas cedar fever unique among North American regional allergies. The timing is driven by the tree's reproductive biology: J. ashei evolved to release pollen during winter cold fronts, which provide the dry, windy conditions ideal for long-distance pollen dispersal. Patients who relocate to Central Texas from pollen-calendar regions where December has zero tree pollen often spend their first winter convinced they have a seasonal cold, only to be properly diagnosed with cedar fever after testing.

No, though they are closely related. Mountain cedar is Juniperus ashei, native to Central Texas and producing the most intense pollen season (December–February) with the highest allergenicity per grain of any Cupressaceae species. Eastern red cedar is Juniperus virginiana, distributed across the eastern half of North America from Maine to Florida, pollinating February through April. Both species produce pectate lyase allergens (Jun a 1-equivalent) with strong cross-reactivity. A patient sensitized to mountain cedar will typically also react to eastern red cedar. However, J. ashei is approximately 20 times more allergenic than Mediterranean cypress and produces much higher pollen counts than J. virginiana in comparable conditions.

Mountain cedar (Juniperus ashei) pollen differs from other major tree pollens in three important ways. First, its season is winter (December–February) rather than spring, making it the primary aeroallergen when most tree pollen calendars are empty. Second, its major allergen Jun a 1 is a pectate lyase, which belongs to a completely different protein family from birch Bet v 1 (PR-10), sycamore Pla a 1 (invertase inhibitor), or hickory pollen — meaning cedar sensitization develops independently rather than as a cross-reactive extension of other tree sensitizations. Third, cedar pollen counts in Austin and San Antonio regularly exceed 20,000 grains per cubic meter, among the highest recorded globally for any aeroallergen.