The 20 Best Mast Cell Activation Syndrome (MCAS) Doctors Near Me in upland, CA

Find the Top Mast Cell Activation Syndrome (MCAS) Experts and Specialists

Last Updated: 09/26/2026

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MediFind found 5 doctor with experience in Mast Cell Activation Syndrome (MCAS) near upland, CA. Of these, 3 are Experienced and 2 are Advanced.

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5 providers found
    Experienced in Mast Cell Activation Syndrome (MCAS)

    Dr. John A. Fagan
    Family Medicine
    Experienced in Mast Cell Activation Syndrome (MCAS)

    Dr. John A. Fagan
    Family Medicine
    Before you request

    Fagan, John A. Family Practice, Inc.

    10787 Laurel St, 
    Rancho Cucamonga, CA 
     (4.7 miles away)
    909-982-7741
    Languages Spoken:
    English
    See accepted insurances
    Accepting New Patients
    Offers Telehealth

    John Fagan is a primary care provider, practicing in Family Medicine in Rancho Cucamonga, California. Dr. Fagan is rated as an Experienced provider by MediFind in the treatment of Mast Cell Activation Syndrome (MCAS). He is also highly rated in 45 other conditions, according to our data. His clinical expertise encompasses Ehlers-Danlos Syndrome (EDS), Hypertension, Familial Hypertension, and Glucocorticoid-Remediable Aldosteronism. Dr. Fagan is board certified in American Board Of Family Medicine. Dr. Fagan is currently accepting new patients.

    Advanced in Mast Cell Activation Syndrome (MCAS)

    Dr. Basim Z. Abdelkarim
    Gastroenterology
    Advanced in Mast Cell Activation Syndrome (MCAS)

    Dr. Basim Z. Abdelkarim
    Gastroenterology
    Referral may be required

    Basim Z. Abdelkarim, M.D., Inc.

    1310 San Bernardino Rd, 
    Upland, CA 
     (1.0 miles away)
    909-920-0444
    Languages Spoken:
    English
    See accepted insurances
    Offers Telehealth

    Basim Abdelkarim is a Gastroenterologist practicing medicine in Upland, California. Dr. Abdelkarim is rated as an Advanced provider by MediFind in the treatment of Mast Cell Activation Syndrome (MCAS). He is also highly rated in 67 other conditions, according to our data. His clinical expertise encompasses Diverticular Disease, Hemorrhoids, Gastroesophageal Reflux Disease (GERD), Gastrostomy, and Endoscopy. Dr. Abdelkarim is board certified in American Board Of Internal Medicine.

    Experienced in Mast Cell Activation Syndrome (MCAS)
    Experienced in Mast Cell Activation Syndrome (MCAS)
    Referral may be required

    Prohealth Partners, A Medical Group, Inc

    685 N 13th Ave, 
    Upland, CA 
     (1.0 miles away)
    909-981-8383
    Languages Spoken:
    English
    See accepted insurances
    Accepting New Patients
    Offers Telehealth

    Samir Samarany is a Cardiologist practicing medicine in Upland, California. Dr. Samarany is rated as an Experienced provider by MediFind in the treatment of Mast Cell Activation Syndrome (MCAS). He is also highly rated in 30 other conditions, according to our data. His clinical expertise encompasses Aortic Regurgitation, Pediatric Myocarditis, Necrosis, and Coronary Heart Disease. Dr. Samarany is board certified in American Board Of Internal Medicine. Dr. Samarany is currently accepting new patients.

    Learn about our expert tiers
    Advanced in Mast Cell Activation Syndrome (MCAS)
    Advanced in Mast Cell Activation Syndrome (MCAS)
    Referral may be required

    Tricity Mental Health Authority

    2008 N Garey Ave, 
    Pomona, CA 
     (5.9 miles away)
    909-623-6131
    Languages Spoken:
    English, Mandarin
    See accepted insurances
    Offers Telehealth

    Jonson Lin is a Psychiatrist practicing medicine in Pomona, California. Dr. Lin is rated as an Advanced provider by MediFind in the treatment of Mast Cell Activation Syndrome (MCAS). He is also highly rated in 3 other conditions, according to our data. His clinical expertise encompasses Major Depression, Mast Cell Activation Syndrome (MCAS), Seasonal Affective Disorder (SAD), and Obsessive-Compulsive Disorder (OCD).

    Experienced in Mast Cell Activation Syndrome (MCAS)

    Dr. Yen I. Lai
    Family Medicine
    Experienced in Mast Cell Activation Syndrome (MCAS)

    Dr. Yen I. Lai
    Family Medicine

    Office

    1343 E Gladstone St Ste 100, 
    Glendora, CA 
     (11.8 miles away)
    909-971-9888
    Languages Spoken:
    English
    See accepted insurances

    Yen Lai is a primary care provider, practicing in Family Medicine in Glendora, California. Dr. Lai is rated as an Experienced provider by MediFind in the treatment of Mast Cell Activation Syndrome (MCAS). She is also highly rated in 13 other conditions, according to our data. Her clinical expertise encompasses Aromatase Deficiency, Renal Hypomagnesemia Type 2, Methylmalonic Acidemia with Homocystinuria, and Homocystinuria.

    Showing 1-5 of 5

    Last Updated: 09/26/2026

    What is the definition of Mast Cell Activation Syndrome (MCAS)?

    Mast cell activation syndrome (MCAS) causes a person to have repeated severe allergy symptoms affecting several body systems. In MCAS, mast cells mistakenly release too many chemical agents, resulting in symptoms in the skin, gastrointestinal tract, heart, respiratory, and neurologic systems. Mast cells are present throughout most of our bodies and secrete different chemicals during allergic reactions. Symptoms include episodes of abdominal pain, cramping, diarrhea, flushing, itching, wheezing, coughing, lightheadedness and rapid pulse and low blood pressure. Symptoms can start at any age, but usually begin in adulthood. The cause of MCAS is unknown. Diagnosis is based on the symptoms, clinical exam, and specific laboratory testing. Other conditions may need to be excluded before MCAS can be diagnosed.

    When should I see a Mast Cell Activation Syndrome (MCAS) doctor near upland, CA?

    There are various reasons why you may want to see a specialist, such as: 

    • Your primary care provider recommends it. 
    • Your condition requires expert knowledge and specialized care. 
    • Your symptoms persist or worsen despite treatment. 
    • You need specialized testing or procedures. 
    • You want a second opinion.  

    What should I consider when choosing a Mast Cell Activation Syndrome (MCAS) doctor near upland, CA?

    It’s important to see a provider with expertise in your specific condition. Each provider profile in MediFind’s doctor database includes information on which conditions they treat, years of experience, research contributions, languages spoken, insurance plans accepted, and more.  

    How do I find the best Mast Cell Activation Syndrome (MCAS) doctor near upland, CA?

    You can find a Mast Cell Activation Syndrome (MCAS) doctor in any of the 10 largest U.S. cities by clicking below:

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    How does MediFind rank Mast Cell Activation Syndrome (MCAS) doctors near upland, CA?

    MediFind’s rankings are based on a variety of data sources, such as the number of articles a doctor has published in medical journals, participation in clinical trials and industry conferences, as well as the number of patients that provider sees for a given condition. Note that MediFind’s provider database is not based on user reviews, and providers do not pay to be included in the database. 

    What types of insurance are accepted by Mast Cell Activation Syndrome (MCAS) doctors near upland, CA?

    Most profiles in MediFind’s doctor database include a list of insurance plans accepted by that provider. However, it’s a good idea to contact the provider’s office to make sure they still accept your insurance, then doublecheck by contacting your insurance plan to confirm they’re in network. 

    How can I book an appointment online with a Mast Cell Activation Syndrome (MCAS) doctor near upland, CA?

    MediFind offers direct scheduling for certain providers using the “Request Appointment” button on that provider’s profile. If the schedule option is not available for a provider, tap the red “Show Phone Number” button on their profile to get their contact information. If you prefer to find providers who offer online scheduling, select “Schedules online” under the “Availability” category of the filter feature on the left side of the Mast Cell Activation Syndrome (MCAS) doctor search results page. 

    Why is it important to get a second opinion from a different Mast Cell Activation Syndrome (MCAS) doctor?

    Second opinions are an opportunity to confirm a diagnosis and its root cause, learn about alternative treatment options, or simply gain peace of mind. Many people, especially those with serious diagnoses, get second opinions so they can understand all their options and make informed decisions, so don’t hesitate to get one if you have any doubts or need more information or clarification regarding your care. Note that some insurance plans require second opinions, while others don’t cover second opinions, so be sure to confirm with your insurance provider first.   

    How can I prepare for my appointment with a Mast Cell Activation Syndrome (MCAS) doctor near upland, CA?

    Prepare for your appointment by gathering the following items: 

    • Copies of medical records (dating back at least one year) 
    • Your medical history, including illnesses, medical conditions, surgeries, and other doctors you see 
    • Family history of disease 
    • List of current prescription drugs, over-the-counter medicines, vitamins, and herbal remedies or supplements including names and doses 
    • Allergies to medications, food, latex, insects, etc.  
    • List of questions and concerns 
    • Your insurance card 

    You might also contact the provider’s office to see if they offer transportation or childcare services or if you’re allowed to bring a loved one for support or to take notes during your visit. 

    What questions should I ask my Mast Cell Activation Syndrome (MCAS) doctor?

    Here are some sample questions: 

    • Can you explain in simple terms what this condition is and how it’s treated? 
    • What symptoms or side effects should I watch for? 
    • What tests will be involved, and when can I expect results? 
    • Are there other specialists I need to see? 
    • What’s the best way to reach you if I have follow-up questions? 

    How can I learn about the latest clinical trials and research advances my Mast Cell Activation Syndrome (MCAS) doctor may know about?

    MediFind’s Clinical Trials tool asks you a series of questions to help you narrow down your search by health condition, age, gender, location, how far you’re willing to travel, and more. Each question you answer filters down the number of trials until you find the ones that are most relevant to you. 

    MediFind’s Latest Advances tool features summaries of recent articles published in medical journals. We use cutting-edge technology to scour medical publication databases for the latest research advancements on any given condition, then we simplify this information in a way that’s useful and easy to understand. 

    Can I filter my search to show male or female Mast Cell Activation Syndrome (MCAS) doctors near upland, CA?

    Look for the filter feature on the left side of the Mast Cell Activation Syndrome (MCAS) doctor search results page. Select “Female” or “Male” under the “Gender” category to search for female or male providers exclusively. If the “Any” option is selected, it will pull results for both male and female providers. 

    Can I filter my search to find a Mast Cell Activation Syndrome (MCAS) doctor that offers video calls?

    Look for the filter feature on the left-side of the Mast Cell Activation Syndrome (MCAS) doctor search results page. Select “Offers telehealth visits” under the Availability category to search for providers who offer virtual appointments (video calls). 

    Reviewed on: 11/11/24  

    By: MediFind Medical Staff 

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