Rough Pigweed Allergy Shots: The Ama r 1 Reference Species for Amaranthus SCIT
Rough pigweed (Amaranthus retroflexus) allergy shots are the molecular reference immunotherapy for the entire Amaranthus genus: a positive ImmunoCAP w14 test means IgE to Ama r 1, the Ole e 1-like major allergen that predicts cross-sensitization to all other pigweed species. No FDA-standardized extract exists; SCIT follows a non-standardized 3-5 year protocol per AAAAI Practice Parameters (Cox 2011). Understanding why your 'pigweed' lab test ran against A.
Rough Pigweed Allergy Immunotherapy: How It Works
Allergy immunotherapy is the only long-term treatment that re-trains the immune system to stop overreacting to rough pigweed — rather than just masking symptoms with antihistamines or steroids. By gradually exposing the body to controlled doses of rough pigweed 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 rough pigweed 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 rough pigweed 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 rough pigweed 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 rough pigweed 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 rough pigweed 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 rough pigweed allergy with at-home drops, see how Curex sublingual immunotherapy compares below.
What is Rough Pigweed?
The biology, taxonomy, and clinical fingerprint of Rough Pigweed — the foundation of how SCIT targets it.
Amaranthus retroflexus (redroot pigweed) pollen is ~25 μm, wind-dispersed, and morphologically indistinguishable from Chenopodium album under light microscopy.
- Scientific name
- Amaranthus retroflexus
- Family
- Amaranthaceae (includes former Chenopodiaceae per APG IV)Amaranth family
- Type
- Annual weed pollen
- Native to
- North America; now cosmopolitan worldwide as a ruderal weed
- Allergen proteins
- Ama r 1 (Ole e 1-like, major)Ama r 2 (profilin, pan-allergen)
- Particle size
- ~25 μm
- Avoidance difficulty
- Nearly impossible
How Rough Pigweed Allergy Presents
Symptoms by body system — useful for distinguishing Rough Pigweed sensitivity from overlapping allergies and infections.
Respiratory
- Seasonal rhinitis with profuse nasal discharge and congestion, August-October
- Sneezing fits triggered by outdoor exposure during peak midday pollen dispersal
- Allergic asthma exacerbation during late-summer pigweed peak
- Post-nasal drip and chronic throat clearing during pollen season
- Sinusitis and facial pressure overlapping with fall weed season
Ocular
- Intense itching and redness of eyes (allergic conjunctivitis)
- Watery eyes worsened by outdoor wind exposure
- Periorbital puffiness on high pollen-count days
- Contact lens intolerance during August-October season
Dermal
- Contact urticaria from direct handling of rough pigweed plants
- Eczema flare in atopic patients during pollen season
- Pruritus of exposed skin on high-count outdoor days
Systemic
- Fatigue and cognitive fog during prolonged seasonal exposure
- Sleep disruption due to nasal congestion
- Profilin (Ama r 2) cross-reactivity may produce OAS symptoms with some raw fruits and vegetables
- Reduced athletic performance during August-October season in sensitized athletes
When a patient comes in with a positive 'pigweed' ImmunoCAP, that test is measuring IgE to A. retroflexus extract — which contains Ama r 1. A single positive w14 result tells us the patient's immune system recognizes the Ama r 1 protein, and that means they are sensitized to essentially all Amaranthus species. The A. retroflexus extract is not just one species' test; it is the reference for the entire genus.
When & Where Rough Pigweed Peaks
Allergen intensity by month and by state. Useful for timing SCIT start dates and travel planning.
12-Month Intensity
Peak: mid-August through late September across most US and European ranges· ~10-12 weeks of intense exposure; Anderegg 2021 (PNAS) documented a 20-day earlier onset in North America 1990-2018
US Exposure Map
12 high-intensity statesWhat Rough Pigweed Cross-Reacts With
Patients sensitized to one allergen often react to others sharing similar proteins. This map shows the documented molecular overlaps.
Ama r 1 (Ole e 1-like) and Ama r 2 (profilin) in A. retroflexus cross-react broadly within Amaranthaceae: virtually all Amaranthus species share Ama r 1, while Ama r 2 profilin cross-reacts with profilins in Russian thistle (Sal k 4), lamb's quarter (Che a 2), kochia, and even grass and ragweed pollen (Tehrani 2010 IJAAIM; Weber 2007 JACI).
Pooled Amaranthus extract; A. retroflexus is the primary reference species in the blend
A. palmeri has no species-specific allergens; fully captured by Ama r 1 cross-reactivity
Is SCIT Right for Your Rough Pigweed Allergy?
Answer 5 questions to see whether rough pigweed allergy shots match your clinical profile.
How severe are your rough pigweed symptoms (August-October)?
The Rough Pigweed SCIT Protocol
Rough pigweed SCIT uses a non-standardized A. retroflexus extract; the extract is the clinical reference for the Amaranthus genus and is often compounded with other fall-weed allergens in a mixed vial for polysensitized patients.
Incremental dose escalation from 1:10,000 w/v to the maintenance concentration. The 30-minute post-injection observation period is mandatory to identify and treat any systemic reaction. Your allergist evaluates the local wheal-and-flare response at each visit before approving the next dose increment. Asthmatic patients may receive a pre-injection spirometry check.
Once the maintenance dose is established, monthly injections sustain immunological tolerance. The rough pigweed extract is frequently compounded with Russian thistle, lamb's quarter, and ragweed in a single vial for fall-season polysensitized patients. Symptom benefit is expected to deepen with each passing fall season. Epinephrine auto-injector should be available throughout treatment.
The AAAAI Practice Parameter (Cox 2011) supports discontinuation after 3-5 years of maintenance in patients who have achieved good control. Many patients retain clinically meaningful benefit even after stopping injections, suggesting immunological reprogramming rather than purely symptomatic suppression.
Extract Concentration Ladder
You progress through each vial during build-up. Concentration increases ~10x per step.
What the Research Shows for Rough Pigweed SCIT
Rough pigweed SCIT lacks a species-specific RCT, but family-level Amaranthaceae data and weed-pollen immunotherapy practice parameters support meaningful efficacy across fall-weed sensitization patterns.
- Symptom score reduction — Salsola SCIT (family-level Amaranthaceae extrapolation)42%Tabar AI et al. 2014, JACI 134:99-105, N=48 (Salsola kali SCIT RCT; closest family evidence)
- Weed-pollen SCIT medication score reduction50%Cox L et al. 2011, JACI 127:S1-55 (AAAAI Practice Parameter — weed-pollen SCIT data)
- Sensitization prevalence — A. retroflexus in Mediterranean pollen-allergic patients22%Asero R et al. 2009, Int Arch Allergy Immunol (southern Italian sensitization rate 12-22%)
No published DBPC-RCT has studied A. retroflexus SCIT specifically. The Tabar 2014 JACI Salsola RCT provides the strongest within-family evidence for Amaranthaceae immunotherapy. Observational evidence and practice-parameter consensus support rough pigweed SCIT as effective for fall rhinitis and asthma. Patients should discuss the evidence extrapolation honestly with their allergist when making an immunotherapy decision.
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Rough Pigweed SCIT Side Effects
Rough pigweed SCIT side effects are consistent with the standard inhalant SCIT profile — local injection-site reactions are common and manageable; systemic reactions are uncommon; anaphylaxis is rare but requires mandatory at-home observation to manage promptly.
Local reactions
4 documentedSystemic reactions
4 documentedSystemic reactions are manageable and rarely life-threatening when epinephrine is on hand and dosing is supervised — exactly what Curex's at-home program provides: a prescribed epinephrine auto-injector confirmed on hand, a board-certified allergist overseeing the plan, and your first dose plus every escalation supervised live over Zoom. Patients with poorly controlled asthma should have their asthma optimized before starting SCIT.
SCIT vs Alternatives for Rough Pigweed
Rough pigweed-sensitized patients have four main treatment options, distinguished primarily by long-term disease modification versus ongoing symptom control.
| Criterion | At-Home SCIT (Curex)Best | SLIT | Avoidance | Medications |
|---|---|---|---|---|
| Effectiveness | High — family-level evidence | Moderate — European data | Minimal — wind-pollinated | Good symptom control |
| 5-yr cost | $3,500-$15,000 | $1,500-$5,000 | Low | $500-$2,000/yr |
| Duration | 3-5 years | 3-5 years | Ongoing | Ongoing daily use |
| Convenience | Self-administered weekly then monthly at home with Curex | Daily home dosing | Very difficult Aug-Oct | Daily pills/sprays |
| Safety | Prescribed epi on hand; first dose Zoom-supervised | Lower systemic risk | Safe | Safe long-term |
| Lasting effect | Yes — post-treatment | Emerging evidence | No | No — symptoms return off meds |
At-Home SCIT (Curex)Best
SLIT
Avoidance
Medications
For patients with confirmed Ama r 1 sensitization and inadequate medication control, SCIT is the only disease-modifying option — and Curex makes it available without weekly clinic visits. Curex delivers personalized rough pigweed immunotherapy as one weekly at-home shot for $129/month all-inclusive: a serum sterile-compounded to USP <797>, a board-certified allergist overseeing your plan, a prescribed epinephrine auto-injector confirmed on hand, and your first dose plus every dose change supervised live over Zoom.
What Rough Pigweed SCIT Actually Costs
Most US insurers cover rough pigweed SCIT under standard allergy benefits when ordered by a board-certified allergist. Prior authorization is routinely required; your allergist's billing team typically handles this process. Actual out-of-pocket cost depends on your plan's deductible and co-insurance. Curex at-home IgE testing identifies specific rough pigweed 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.
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Rough Pigweed SCIT — Frequently Asked
Quick answers to the questions patients ask most before starting treatment.
Amaranthus retroflexus (rough pigweed) is the immunological reference for the genus because it is the only Amaranthus species with formally characterized WHO/IUIS allergens — Ama r 1 (Ole e 1-like protein) and Ama r 2 (profilin). Palmer amaranth (A. palmeri), despite being the most aggressive agricultural superweed in the Southeast and Midwest, has no species-specific IUIS-named allergens as of 2024 (WHO/IUIS database). This means allergy labs run the A. retroflexus extract under ImmunoCAP code w14 to test for any Amaranthus sensitization — a positive result at A. retroflexus accurately captures cross-reactive IgE to all Amaranthus species, including Palmer amaranth. The test is measuring Ama r 1 reactivity, not species-specific A. retroflexus antibodies.
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.