Board-certified allergist · Merced
Your allergy allergist in Merced, CA
Sierra Allergy is the northern Central Valley’s board-certified allergy and immunology specialist. Comprehensive testing, evidence-based treatment, and now open Saturdays for working families across Merced County.
Visit us
Merced office
- Address: 105 W El Portal Dr, Suite B, Merced, CA 95348
- Phone: (209) 349-8526
- Fax: (209) 349-8518
- Hours: Monday–Saturday, 9:00 AM to 6:00 PM
- Parking: Free on-site parking, ADA-accessible entrance.
- Getting here: Conveniently located near Highway 99 and downtown Merced. Easy access from Atwater, Livingston, Los Banos, and surrounding Central Valley communities.
Lead specialist
Dedicated allergist & immunologist delivering care
Muhammad Hassan Bashir, MD, is a board-certified physician in internal medicine and a distinguished allergist and immunologist at Sierra Allergy Asthma and Sinus Center. Dr. Bashir completed his specialized training in allergy and immunology at Stanford University Medical Center. With over 15 years of compassionate excellence, he has helped countless individuals overcome their allergy and immunology challenges through personalized, evidence-based care.
- 15+ years of compassionate excellence
- Stanford-trained allergist
- Professional & knowledgeable expert
Trusted by Central Valley patients
Award-winning care
Recognized in Merced for outstanding patient outcomes and reviews.
Fresno & Merced offices
Convenient locations for Central Valley patients.
Agency-accredited
Board-certified physicians, evidence-based treatments.
Patient-focused
Same-week appointments and personalized treatment plans.
Insurance providers we accept
Note: These are not the only insurance providers we accept. We also work with other insurance companies not listed above. Please contact us to verify your coverage.
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Local trigger expertise
We know what blooms in Merced County
Our testing panels are calibrated to the Merced County environment — almond and pistachio orchards, dairy operations, summer ag dust, fall ragweed, and the wide swings between Valley fog and clear-sky days. Generic regional panels often miss what’s actually triggering you.
Most patients walk out of their first visit with concrete answers: what they react to, by how much, and what to do about it.
Built around your week
Saturday hours, fast results
Our Merced office is open Monday through Saturday. Skin testing results are immediate; blood tests typically return within a week. We send a written summary to your primary care provider after every visit, so your care stays coordinated.
Telehealth follow-ups are available for medication management, so you don’t have to keep taking time off work to manage chronic symptoms.
Book an online or in-person appointment!
Treatments we offer
Beyond antihistamines
We offer allergy shots, sublingual immunotherapy, biologic injections (for severe allergy and asthma), oral food challenges, and contact dermatitis patch testing. Whatever combination is right for you, we’ll explain why — and what the realistic outcome looks like.
Why choose Sierra Allergy Asthma and Sinus Center
We are dedicated to helping you heal, feel better, and live fully. Here's why you should choose us:
- Personalized Care
- Expert Team
- Convenient Locations
- Trusted Reputation
- Modern Facility
- Advanced Technology
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FAQs
Frequently Asked Questions
Do I need a referral to see an allergist in Merced?
It depends on your insurance. HMO plans usually require a referral; PPO plans generally do not. Call us and we will help verify before your visit.
How is Sierra Allergy different from urgent care?
Urgent care can address an immediate symptom flare. Allergists diagnose and treat the underlying cause — so you stop needing urgent care for the same thing.
Do you serve Atwater and Livingston?
Yes — about 25% of our Merced patients commute in from Atwater, Livingston, Winton and Le Grand. Most appointments fit easily into a lunch break with our Saturday and same-week options.
What if I've already had allergy testing elsewhere?
Bring the report. In many cases we can build on existing testing rather than repeat it. Sometimes we recommend a small expanded panel for triggers the original test missed.
Can children get allergy shots?
Yes. We typically begin immunotherapy at age five or older, depending on the child’s ability to communicate symptoms and tolerate the injection.
What our patients say
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