Can a Sore Throat be a Side Effect of Antibiotics?

October 12, 2025 •

5 min read

According to research, a sore throat can sometimes be a side effect of antibiotics. While often mistaken for the original infection, a new or worsening sore throat during antibiotic treatment can be a symptom of conditions like oral thrush or an allergic reaction.

Quick Summary

Taking antibiotics can sometimes lead to a sore throat, which may stem from several conditions, including an overgrowth of yeast causing oral thrush, an allergic reaction to the medication, or a rare but serious side effect called drug-induced neutropenia. Recognizing the specific symptoms can help determine the underlying cause and the appropriate next steps. This guide details the different reasons a sore throat can develop while on antibiotics and when to seek medical attention.

Key Points

Oral Thrush Causes Sore Throat: Antibiotics can kill beneficial bacteria, allowing the yeast Candida to overgrow in the mouth and throat, causing oral thrush.
Allergic Reaction Symptom: A sore throat, particularly with swelling or tightness, can be a sign of a mild or severe allergic reaction to an antibiotic.
Neutropenia Risk: In rare cases, some antibiotics can cause drug-induced neutropenia, a low white blood cell count that increases infection risk, leading to symptoms like a severe sore throat.
Know the Signs: Differentiating between oral thrush (white patches), an allergic reaction (swelling, hives), and neutropenia (fever, severe pain) is crucial for seeking appropriate medical care.
Seek Medical Advice: Always consult a healthcare provider for any new or worsening symptoms while taking antibiotics, especially if they are severe, such as difficulty breathing.
Complete Your Treatment: Continue the full course of antibiotics as prescribed to prevent antibiotic resistance, but report any concerning new side effects to your doctor.

Understanding the Link Between Antibiotics and Sore Throats

Many people take antibiotics to treat bacterial infections, including those causing a sore throat. So, it can be confusing when a new or worsening sore throat develops during or after a course of medication. The sore throat is typically not a direct side effect of the drug itself, but rather an indirect consequence related to how the antibiotic affects the body's natural balance of microorganisms or, less commonly, an immune response.

The most common culprits are oral thrush, allergic reactions, and the rare but serious condition of drug-induced neutropenia. Recognizing the signs of each is crucial for proper treatment and management.

Oral Thrush: A Common Fungal Culprit

Oral thrush, or candidiasis, is a yeast infection of the mouth and throat caused by an overgrowth of the fungus Candida albicans. Antibiotics can disrupt the normal balance of bacteria in the body, which typically keep Candida in check. This allows the fungus to multiply unchecked, leading to an infection.

Symptoms of oral thrush often include:

White, creamy lesions: These patches or spots can appear on the tongue, inner cheeks, gums, tonsils, or roof of the mouth.
Soreness and redness: The areas under the white patches may be red and painful.
Difficulty swallowing: Inflammation can make eating and swallowing uncomfortable.
Loss of taste: Some people experience a reduced sense of taste.
"Cottony" feeling: A characteristic dry, cotton-like sensation in the mouth is common.

Treatment for oral thrush typically involves antifungal medication, such as lozenges or a mouthwash. Your doctor may also recommend eating yogurt with live cultures to help restore the balance of healthy bacteria.

Allergic Reactions: An Immune System Response

An allergic reaction to an antibiotic can manifest in various ways, with throat swelling and tightness being a serious, and sometimes life-threatening, symptom. The immune system mistakenly identifies the antibiotic as a harmful substance and triggers a response. Allergic reactions can range from mild rashes to severe anaphylaxis.

Key symptoms of an allergic reaction include:

Sudden throat tightness or swelling: This can be a sign of a severe reaction and requires immediate medical attention.
Hives or itchy rash: A raised, red, and itchy rash is a common sign of a mild to moderate allergy.
Trouble breathing: Wheezing or difficulty breathing can occur with swelling of the throat and airways.
Facial or tongue swelling: Swelling of the face, lips, or tongue can accompany throat swelling.

If you experience any of these symptoms, especially difficulty breathing or swelling, stop taking the medication and seek immediate medical help. Penicillin allergies are among the most common antibiotic allergies.

Drug-Induced Neutropenia: A Rare but Serious Cause

In rare cases, antibiotics can trigger drug-induced neutropenia, a condition characterized by a dangerously low count of neutrophils, a type of white blood cell crucial for fighting infection. The throat pain in this case is not a direct side effect, but rather a symptom of a bacterial infection that the body can no longer fight effectively due to a compromised immune system.

Symptoms of drug-induced neutropenia can include:

Fever and chills: A persistent fever is a major sign of an underlying infection.
Severe sore throat: An unusually painful sore throat or mouth sores may develop.
Fatigue and malaise: General feelings of being unwell and tired are common.

This condition requires immediate medical attention, and the antibiotic must be discontinued.

Other Potential Causes of a Sore Throat

Beyond these main issues, other less common factors can contribute to a sore throat during antibiotic treatment:

Pill Esophagitis: Some antibiotics, if not taken with enough water or if taken while lying down, can irritate the esophagus, causing a sensation of chest and throat pain.
Jarisch-Herxheimer Reaction: This is a short-term, immune-mediated reaction that can occur after starting antibiotics for certain bacterial infections, such as syphilis. It can cause flu-like symptoms, including a sore throat.

Oral Thrush vs. Allergic Reaction: A Comparison


Characteristic	Oral Thrush	Allergic Reaction	Drug-Induced Neutropenia
Symptom Type	Fungal infection symptoms	Immune system overreaction	Infection due to low white blood cells
Onset	Usually develops gradually over a few days during or after antibiotic course.	Can occur very rapidly (within minutes to hours) or be delayed.	Can occur within weeks of starting the drug.
Key Symptoms	White patches in the mouth and throat, redness, loss of taste, cottony feeling.	Swelling of the throat/tongue, hives, rash, difficulty breathing.	High fever, severe sore throat, mouth sores, chills.
Associated Pain	Burning or soreness in the mouth and throat.	Tightness or swelling sensation in the throat.	Pain from severe pharyngeal or oral infection.
Action Required	Consult a doctor for antifungal treatment. Continue antibiotics unless advised otherwise.	Immediate medical emergency if severe (e.g., swelling, breathing issues). Stop medication and contact a doctor for mild cases.	Immediate medical emergency. Discontinue the drug and seek urgent care.

When to Contact a Healthcare Professional

While a minor sore throat might resolve on its own, certain symptoms warrant immediate medical attention. It is crucial to monitor your body's response while taking antibiotics. Always complete the full course of antibiotics as prescribed to prevent antibiotic resistance, but if new symptoms appear, it is important to communicate them to your doctor.

If your sore throat is accompanied by symptoms such as a high fever, severe difficulty swallowing, hives, facial swelling, or trouble breathing, you must seek emergency medical care immediately. Prompt action can prevent life-threatening complications.

Conclusion: Navigating Sore Throats During Antibiotic Use

Can a sore throat be a side effect of antibiotics? The answer is yes, but it is rarely a simple one. The sore throat is often an indication of another underlying issue triggered by the medication, such as oral thrush, a drug allergy, or, in very rare instances, neutropenia. Being aware of the specific symptoms associated with each condition is the first step toward receiving the correct diagnosis and treatment. Always discuss any new or worsening symptoms with your healthcare provider to ensure your safety and well-being. Never self-diagnose or alter your medication regimen without professional guidance. Staying informed and proactive is key to a healthy recovery. For general information on antibiotic side effects, one can refer to the resource provided by the National Institutes of Health.

Frequently Asked Questions

An antibiotic does not directly cause a sore throat in most cases. It can, however, disrupt the balance of bacteria in your body, allowing opportunistic infections like oral thrush (a yeast infection) to develop. In other cases, a sore throat is a symptom of a serious allergic reaction or a rare blood disorder called neutropenia.

Oral thrush is a fungal infection of the mouth and throat caused by an overgrowth of Candida albicans. Antibiotics can kill the normal, healthy bacteria in your body that typically keep Candida in check, allowing the fungus to flourish and cause an infection.

An antibiotic allergy might cause a sore throat accompanied by swelling or tightness in the throat, hives, an itchy rash, or difficulty breathing. These symptoms often appear rapidly after taking the medication. If you experience any throat swelling or breathing issues, seek emergency medical care immediately.

Drug-induced neutropenia is a very rare but serious condition where an antibiotic causes a dangerously low white blood cell count. This makes you highly susceptible to infection, and a severe sore throat can be one of the presenting symptoms of such an infection. It is a medical emergency that requires prompt treatment.

No, you should never stop taking antibiotics without consulting your doctor. Prematurely stopping antibiotics can lead to antibiotic resistance and a return of the original infection. Instead, contact your doctor to determine the cause of the sore throat and what steps to take next.

If oral thrush is diagnosed, your doctor will likely prescribe an antifungal medication, which may come in the form of a mouthwash or lozenges. In some cases, over-the-counter options like eating yogurt with live cultures may help restore the balance of microorganisms in your mouth.

If you experience throat tightness, swelling, or difficulty breathing, this could be a sign of a severe allergic reaction (anaphylaxis). Stop taking the antibiotic and call 911 or go to the nearest emergency room immediately.