For people living with type 2 diabetes, managing blood sugar levels is already a daily balancing act. Every meal, activity, and medical condition can tip the scales. When an infection like a sinus infection enters the picture, it can make things even more complicated — and frustrating.

You might wonder: Can a sinus infection actually raise blood sugar levels? The short answer is yes — infections can lead to higher blood sugar levels. Although research specifically on sinus infections and blood sugar is limited, studies show that infections of many kinds can trigger stress responses in the body. These responses raise blood glucose levels and make it harder for insulin to work properly. On rare occasions, this added challenge may sometimes lead to serious complications for people with type 2 diabetes if not managed carefully.

Keep reading to learn how sinus infections — and other illnesses — can disrupt your blood sugar control, why infections may hit harder when you’re living with diabetes, and what steps you can take to protect yourself and stay on track during illness.

How Sinus Infections Can Lead to High Blood Sugar Levels

A sinus infection (also called sinusitis) happens when the tissues lining the nasal cavity and sinuses — the hollow spaces in your skull around your nose and eyes — become swollen and inflamed. This swelling is often caused by a viral, bacterial, or fungal infection​. In some cases, chronic sinusitis can develop if the inflammation lasts 12 weeks or longer.

When your body detects an infection like sinusitis, it triggers a defensive stress response. Stress hormones like cortisol and adrenaline are released to help fight off the infection. These hormones are essential for the immune system, but they also make it harder for insulin to move sugar out of the bloodstream and into your cells.

As a result, blood sugar levels can rise sharply — a condition called hyperglycemia. For people living with type 2 diabetes, infections like sinusitis can create a perfect storm where blood sugar becomes harder to control. In rare cases, if high blood sugar isn’t managed carefully, it can lead to serious complications like diabetic ketoacidosis (DKA).

While sinus infections may be a trigger, many other infections — such as the flu, urinary tract infections (UTIs), or yeast infections — can have a similar effect on blood sugar levels.

For many people living with diabetes and not knowing it, an episode of DKA triggered by an infection can lead to the diagnosis of diabetes.

Why Blood Sugar Control Gets Tougher During Infections

Infections like sinusitis don’t just raise blood sugar — they can also make it harder for your body to bring those levels back down.

When you’re fighting an infection, your immune system works overtime. Stress hormones surge to help your body respond to the infection, but they also raise blood glucose levels. At the same time, high blood sugar can weaken your immune response, making it harder for your body to heal.

It’s a two-way street:

• Infections can push blood sugar levels higher.
• High blood sugar can make infections worse and slow down recovery.

Research shows that people with poorly managed type 2 diabetes may face a higher risk of developing infections, including respiratory infections like sinusitis​​. Persistent infections can keep blood glucose levels elevated for weeks, creating a cycle that’s hard to break without targeted care.

That’s why tracking blood sugar, monitoring for ketones, and managing carbohydrate intake carefully during an illness are crucial parts of an effective sick-day plan for people living with type 2 diabetes​​.

Are Infections More Dangerous for People With Type 2 Diabetes?

While most sinus infections clear up on their own, people with type 2 diabetes may be at an increased risk for serious complications. This is because diabetes can weaken the immune system, making it harder to fight off infections and heal properly.

Though rare, untreated or poorly managed sinus infections can lead to more severe infections or spread to nearby areas like the eyes or brain. And as noted, when blood sugar levels stay high, the body’s ability to heal slows down​​.

What About Other Types of Infections?

People living with type 2 diabetes may also face higher risks from other types of infections — not just sinusitis. Respiratory illnesses like the flu and pneumonia, UTIs, skin infections, and yeast infections can all become more serious when blood sugar levels are not well managed.

Infections may last longer, respond more slowly to treatment, or lead to more severe complications compared to those of people without diabetes.

Managing blood sugar carefully — even during minor illnesses — is key to reducing these risks. Staying alert to early signs of infection and reaching out to your healthcare provider if symptoms don’t improve can help you recover faster and prevent more serious health problems.

Managing a Sinus Infection With Diabetes

If you develop a sinus infection, here are some ways to protect your health:

• Monitor blood sugar levels more frequently. Track trends and share them with your healthcare provider.
• Stay hydrated. Fluids help thin mucus and support healing.
• Follow your sick-day plan. Many people with type 2 diabetes have a plan in place for managing blood sugar during illness​.
• Avoid sugary supplements. Some cough syrups and lozenges contain carbohydrates that can raise blood sugar.
• Rest and manage stress. Both help reduce the strain on your immune system and blood sugar regulation.
• Ask about safe over-the-counter options. Some decongestants are safer than others for people with diabetes​.

Managing a sinus infection carefully helps you recover faster and prevents blood sugar problems. This also applies to illnesses like the flu or a UTI. Check your blood sugar regularly, follow your diabetes care plan, and watch your symptoms closely. If you’re unsure how to manage diabetes during sickness — or don’t have a sick-day plan yet — talk to your healthcare provider now to help you get better quicker when you’re ill.

When To Seek Medical Attention

It’s important to know when a sinus infection needs a healthcare provider’s attention. Contact your doctor if:

• Symptoms worsen or do not improve after a few days of self-care (like nasal rinses and hydration).
• The infection recurs (comes back) over and over.
• Blood sugar levels remain high even after adjusting your usual management plan.
• Over-the-counter medications (like decongestants) worsen your blood sugar levels. (Some cold medicines can spike blood sugar​.)

Never ignore new or worsening symptoms, as they may signal a serious infection and require emergency care​. These include:

• High fever (over 103 degrees Fahrenheit)
• Confusion
• Changes in vision
• Swelling, pain, or discoloration around the eyes
• Seizures
• Neck stiffness

Although this advice is about sinus infections, it also applies to other illnesses. If you have a lasting fever, severe pain, unusual swelling, trouble breathing, or high blood sugar that won’t go down, get medical help right away. Diabetes can slow your recovery, so it’s better to act early to stop minor infections from becoming serious.

Protecting Yourself Against Future Infections

There are several steps you can take to help prevent sinus infections:

• Wash your hands regularly, especially during cold and flu season.
• Stay well hydrated by drinking water throughout the day.
• Breathe in steam, either by taking a hot shower or pouring boiled water into a pan and inhaling it.
• Manage allergies carefully, as nasal allergies can increase your risk of sinus infections.
• Wear a mask in crowded spaces like airplanes, public transit, or clinics to reduce exposure to viruses that can trigger sinus infections.
• Take vitamin D supplements during the cold season.

If you experience frequent or recurring sinus infections, let your doctor know. They may recommend additional steps — such as allergy management, preventive medications, or specialist care — to help you stay healthier.

Staying up to Date on Vaccines

Vaccines are an important line of defense against infections that can hit harder when you have diabetes. Staying up to date on recommended vaccines helps lower your risk of serious complications if you do get sick.

Talk to your doctor about:

• Influenza (flu) vaccine yearly
• COVID-19 vaccines and boosters
• Pneumonia vaccine
• Tetanus, diphtheria, and pertussis (Tdap) booster
• Shingles vaccine (for adults over 50)
• Hepatitis B vaccine

In general, people with type 2 diabetes are strongly encouraged to follow vaccination schedules unless they have a specific medical reason to delay or avoid a vaccine — such as a severe allergy to a vaccine component or a weakened immune system from another condition or treatment. Your doctor can help you decide the safest vaccine plan for your individual health needs.

Supporting Your Immune System

Taking care of your body helps your immune system work at its best. Healthy habits include:

• Keeping your blood sugar levels within your target range
• Eating a balanced, nutrient-rich diet
• Staying physically active
• Managing stress
• Getting enough sleep every night

Being Mindful of Your Surroundings

In crowded indoor spaces — like airports, planes, clinics, and public transportation — wearing a mask can add an extra layer of protection, especially during cold and flu season.

Small daily actions can make a big difference when it comes to preventing infections. Protecting yourself doesn’t just keep you healthier today — it helps keep your blood sugar more stable and your long-term health on track.

Talk to Your Doctor

Everyone’s diabetes is different. If you have unusual symptoms or trouble controlling blood sugar during an illness, talk to your healthcare provider. Together, you can make a plan to stay safe and get better faster. Trust yourself — you know your body best.

Connect With Others

On DiabetesTeam, the social network for people living with type 2 diabetes and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with diabetes.

Have you ever noticed your blood sugar levels spike when you’re sick, like during a sinus infection or the flu? How do you manage your diabetes care plan when you’re under the weather? Share your experiences in the comments below, or start a conversation by posting on your Activities page.