Red Alder Allergy Shots (SCIT)
Red alder (Alnus rubra) is the first major tree pollen of the year in the Pacific Northwest — arriving as early as late January in Seattle and Portland — and 2024 data from Aglas/Strobl show Aln g 1 can act as a genuine primary sensitizer, not just a birch cross-reactor.
Red Alder Allergy Immunotherapy: How It Works
Allergy immunotherapy is the only long-term treatment that re-trains the immune system to stop overreacting to red alder — rather than just masking symptoms with antihistamines or steroids. By gradually exposing the body to controlled doses of red alder allergen, immunotherapy shifts the underlying allergic response and produces relief that often outlasts treatment by 7–10 years.
There are two evidence-based forms of red alder immunotherapy used today, both built on the same desensitization principle but delivered very differently.
of sustained relief after a complete immunotherapy course — the only allergy treatment with proven long-term effect after stopping.
Allergy Shots (SCIT)
Weekly injections of red alder extract in a clinic, escalating over 3–6 months until a maintenance dose is reached. Continued monthly for 3–5 years. Longest clinical track record for red alder allergy.
- Strongest evidence base for severe and polysensitized patients
- Covered by most insurance plans
- Requires 50–100+ in-person clinic visits across the full course
Allergy Drops / Tablets (SLIT)
Daily drops or dissolvable tablets containing red alder extract, held under the tongue at home. Same desensitization principle, delivered without injections. WHO-recognized as an effective form of allergy immunotherapy since 2001.
- Taken at home — no weekly clinic trips, no needles
- Lower systemic reaction rate than allergy shots
- Curex offers prescription red alder immunotherapy drops with allergist oversight
The rest of this page goes deep on allergen-specific immunotherapy with shots — protocol, efficacy data, side effects, and cost. If you’d rather skip the clinic and treat red alder allergy with at-home drops, see how Curex sublingual immunotherapy compares below.
What is Red Alder?
The biology, taxonomy, and clinical fingerprint of Red Alder — the foundation of how SCIT targets it.
Red alder catkins release pollen as early as late January in the Pacific Northwest — often weeks before any other tree pollen in the region — making it the 'off-season' Fagales allergen most responsible for January and February rhinitis in Seattle and Portland.
- Scientific name
- Alnus rubra Bong.
- Family
- BetulaceaeBirch family
- Type
- Deciduous tree pollen
- Native to
- Pacific Northwest coast of North America (WA, OR, northern CA)
- Allergen proteins
- Aln g 1 (major) — PR-10, ~17 kDa, 88% amino-acid identity with Bet v 1 (Strobl & Lehmann 2024)Aln g 4 — Polcalcin (catalogued at WHO/IUIS)Aln g profilin — pan-allergen (catalogued at WHO/IUIS)
- Particle size
- ~20 μm
- Avoidance difficulty
- Nearly impossible
How Red Alder Allergy Presents
Symptoms by body system — useful for distinguishing Red Alder sensitivity from overlapping allergies and infections.
Respiratory
- Sneezing and nasal discharge beginning in late January or February in PNW cities — weeks before most pollen trackers alert patients
- Nasal congestion that intensifies through February and March as alder catkins reach peak dehiscence
- Wheezing and chest tightness in asthmatic patients sensitive to early Fagales pollen
- Persistent post-nasal drip and morning throat clearing through the 6–8 week alder season
- Worsening symptoms on windy, dry days when pollen counts peak — particularly in riparian and coastal PNW areas
Ocular
- Bilateral eye itching and watering during January–March alder peak in the PNW
- Conjunctival redness and photophobia on high-pollen days
- Morning eye swelling from overnight pollen accumulation on bedding
- Reduced contact lens tolerance during alder season
Dermal
- Oral allergy syndrome (OAS) to raw apple, hazelnut kernel, peach, cherry, carrot, and celery via Aln g 1 / Bet v 1 PR-10 cross-reactivity; heat-labile — cooked forms usually tolerated
- Periorbital dermatitis or eczema flares coinciding with peak alder counts in sensitized patients
- Contact urticaria from direct pollen exposure in highly sensitized individuals
Systemic
- Fatigue from early-winter allergy season that catches PNW patients off guard in January and February
- Sleep disruption from nighttime nasal congestion during the 6–10 week alder window
- Impaired outdoor activity tolerance in the late-winter PNW hiking and cycling season
- Reduced quality of life in the weeks before 'spring' has officially arrived
If you live in Seattle or Portland and your 'spring' allergies start in January, that's red alder — and 2024 data show Aln g 1 can sensitize you on its own, not just as a birch cross-reactor. That's why I sometimes add alder to a birch-anchored SCIT mix even when the patient's only large skin test was to birch — because the two allergens, while 88% identical, can have distinct sensitization pathways.
When & Where Red Alder Peaks
Allergen intensity by month and by state. Useful for timing SCIT start dates and travel planning.
12-Month Intensity
Peak: late January through March in the Pacific Northwest — the first major tree pollen of the year in the region· ~6–10 weeks; climate change has shifted PNW alder peak earlier by ~2–3 weeks compared with 1990 (methodology per Anderegg 2021 PNAS)
US Exposure Map
2 high-intensity statesWhat Red Alder Cross-Reacts With
Patients sensitized to one allergen often react to others sharing similar proteins. This map shows the documented molecular overlaps.
Red alder's Aln g 1 shares 88% amino-acid identity with birch Bet v 1, producing an r=0.994 IgE correlation between alder and birch in Korean cross-sectional data (Choi 2019). PNW patients are often co-sensitized to both, and alder SCIT cross-protects against the subsequent birch season via the shared PR-10 epitope architecture.
Aln g 1 — 88% identity with Bet v 1; r=0.994 IgE correlation (Choi et al., Kosin Med J 2019)
Mal d 1 PR-10 OAS via Bet v 1 homology; heat-labile
Cor a 1.04 — heat-labile PR-10 OAS; see white-birch page for full food table
Pru p 1 — PR-10 OAS; typically tolerated cooked
Alder (Aln g 1) PR-10 Oral Allergy Syndrome
Because Aln g 1 shares 88% identity with Bet v 1, red alder-sensitized patients often develop OAS to the same raw foods as birch-allergic patients — apple, hazelnut kernel, peach, cherry, carrot, and celery. These reactions are heat-labile (cooked forms usually tolerated) and reflect PR-10 cross-reactivity, not a separate food allergy. See the white birch page for the complete PR-10 OAS food table. A board-certified allergist can confirm whether your food reactions are PR-10-driven or involve heat-stable storage proteins via component-resolved testing.
Is SCIT Right for Your Red Alder Allergy?
Answer five questions to assess whether red alder SCIT or a birch-anchored Fagales mix is appropriate for your PNW allergy profile.
How severe are your late-winter PNW allergy symptoms (January–March)?
The Red Alder SCIT Protocol
Red alder SCIT uses non-standardized Alnus extract in the same conventional ladder used for other Betulaceae. Because alder season begins as early as late January, build-up should ideally be initiated in the summer or early fall to reach maintenance dose before peak exposure.
Injections begin at 1:10,000 w/v and increase incrementally. PNW patients with concurrent alder and birch sensitization who are undergoing build-up during the January–May tree season may need slower up-dosing due to active pollen co-exposure. Starting build-up out of season (summer) is preferred. Mandatory 30-minute post-injection observation at all visits.
Monthly maintenance at the target dose sustains alder-specific and cross-protecting Bet v 1 tolerance. Because Aln g 1 and Bet v 1 share 88% identity, patients on a birch-anchored Fagales mix often achieve meaningful alder-season cross-protection via Bet v 1 desensitization alone — the mechanism confirmed in the Itulazax TT-04 alder-season secondary endpoint.
Lasting benefit — typically 7–12+ years — is associated with completing the full course. Because alder's season is compressed into 6–10 winter weeks, patients may underestimate year-to-year benefit without systematic symptom tracking. Encourage diary-keeping to document the season-over-season trajectory.
Extract Concentration Ladder
You progress through each vial during build-up. Concentration increases ~10x per step.
What the Research Shows for Red Alder SCIT
No species-specific SCIT RCT exists for Alnus rubra (US red alder). Clinical use extrapolates from the birch-homologous family evidence — specifically the Itulazax TT-04 trial documenting alder-season symptom reduction as a secondary endpoint — and from the 88% Aln g 1/Bet v 1 sequence identity that places alder within the same immunologic treatment unit as birch.
- Alder-season symptom reduction (birch-homologous immunotherapy)60%Itulazax TT-04 secondary endpoint — alder season; ALK/EMA 2019, N=634 birch-sensitized adults
- IgE correlation (alder vs birch sensitization)99%Choi et al., Kosin Med J 2019 (r=0.994 cross-sectional cohort)
No alder-specific SCIT RCT has been conducted in Alnus rubra — the dominant US species. All efficacy estimates derive from the birch-homologous family evidence base (Itulazax TT-04 alder-season secondary endpoint; Bodtger 2002 and Arvidsson 2002 birch SCIT RCTs). The 88% Aln g 1/Bet v 1 sequence identity, r=0.994 IgE correlation, and 2024 primary-sensitization data (Aglas/Strobl) provide a strong mechanistic and clinical rationale for including alder in a Fagales SCIT mix — but clinicians and patients should understand that direct alder SCIT RCT evidence does not exist for the US population.
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Red Alder SCIT Side Effects
Red alder SCIT side effects follow the standard inhalant SCIT profile. Build-up during the active PNW alder season (January–March) may increase reactivity — starting out of season is preferred.
Local reactions
4 documentedSystemic reactions
4 documentedStarting alder SCIT build-up in summer or early fall — well before the January alder season — is the most important safety and tolerability strategy for PNW patients. Co-exposure to active alder pollen during build-up increases the likelihood of dose-hold events and local reactions.
SCIT vs Alternatives for Red Alder
PNW alder-allergic patients have four main options: Fagales-anchored SCIT — available as a weekly at-home shot with Curex — sublingual drops, avoidance (limited given the urban ubiquity of red alder across the Pacific coast), and daily medications during the winter pollen window.
| Criterion | SCITBest | SLIT | Avoidance | Medications |
|---|---|---|---|---|
| Effectiveness | High — family-level Phase 3 evidence (Itulazax TT-04 alder-season secondary endpoint) | Moderate — no FDA-approved alder SLIT tablet in US; off-label drops are standard extract | Low — red alder is ubiquitous across PNW riparian and coastal areas | Moderate — antihistamines + intranasal steroids for mild-moderate symptoms |
| 5-yr cost | $3,500–$15,000 over 5 years | Varies by provider; drops exist as a general option for alder pollen but are not what Curex offers | Low — HEPA, masks, keeping windows closed | $500–$2,000 over 5 years |
| Duration | 3–5 year course | 3–5 year course | Indefinite — no tolerance change | Indefinite — seasonal use |
| Convenience | At-home weekly self-injection with Curex; start build-up in summer before alder season; first dose and dose changes supervised live over Zoom | Daily at-home — ideal for patients unable to reach a clinic in winter | Moderate inconvenience January–March | High convenience — daily pill or spray |
| Safety | Excellent — alder extract is USP <797> sterile-compounded and lot-tested, dosing is Zoom-supervised by your allergist, a prescribed epinephrine auto-injector is confirmed on hand, plus a 30-minute self-observation | Favorable — no systemic anaphylaxis in SLIT trials | Safe | Generally safe |
| Lasting effect | 7–12+ years after completion | Emerging — likely shorter duration vs SCIT | None — symptoms return each January | None — must take every season |
SCITBest
SLIT
Avoidance
Medications
SCIT is the best option for PNW patients with moderate-to-severe red alder allergy, especially those with confirmed Aln g 1 primary sensitization who may not get full benefit from a birch-only protocol — and with Curex, eligible patients self-administer that shot at home for $129/month, avoiding weekly winter clinic visits, with the first dose and every dose change supervised live over Zoom and a prescribed epinephrine auto-injector confirmed on hand.
What Red Alder SCIT Actually Costs
Alder SCIT is covered by most major US insurers under standard allergy immunotherapy benefits when documented by a positive skin test or specific IgE result and ordered by a board-certified allergist. Because alder is commonly included in a Fagales mix rather than prescribed as a standalone extract, billing often covers the full tree-mix preparation rather than a single allergen. Curex at-home IgE testing identifies specific red alder sensitization before allergist consultations, eliminating the need for an initial skin-test visit.
Cost range varies by deductible, co-insurance, and clinic.
Verify these codes with your insurer to confirm coverage.
Flat monthly subscription — includes consult, prescription, and at-home dosing for sublingual immunotherapy.
See if you qualifyStop guessing about your red alder allergy. Get a plan.
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Red Alder SCIT — Frequently Asked
Quick answers to the questions patients ask most before starting treatment.
In the Pacific Northwest, red alder is the exception to the spring-pollen rule. Alnus rubra catkins begin releasing pollen as early as late January in Seattle, Portland, and coastal Oregon — often the first tree pollen of the year in North America. Climate change has pushed this even earlier (Anderegg 2021 PNAS methodology applied regionally). If your 'spring' allergies start mid-winter and resolve by April, red alder is the most likely culprit. A skin prick test or specific IgE for Aln g 1 through a board-certified allergist can confirm the diagnosis.
This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. Content reviewed by board-certified allergists at Curex.