Can Allergies Make You Nauseous? Here’s Why They Can

Allergies are commonly associated with symptoms like sneezing, itching and congestion, but many people may be surprised to learn that they can also lead to gastrointestinal discomfort, including nausea. While the connection between allergies and nausea might not be immediately apparent, various mechanisms can explain this uncomfortable symptom. Understanding how allergies can affect the body beyond the typical respiratory symptoms is crucial for those who suffer from allergic reactions.

Seven causes for nausea

Nausea can be caused by many different factors, each with its own unique reasons. Let's explore some of the most common causes as noted by the American College of Allergy, Asthma and Immunology (ACAAI).

Allergies

Allergies can trigger nausea through a variety of pathways. When the immune system reacts to allergens, it releases histamines and other chemicals that can affect the gastrointestinal tract. This can lead to symptoms such as nausea, vomiting and even abdominal cramps, especially in cases of food allergies or when allergens cause systemic reactions.

Food poisoning

Food poisoning occurs when contaminated food or beverages are consumed, leading to the ingestion of harmful bacteria, viruses or toxins. Symptoms often include nausea, vomiting, diarrhea and abdominal pain as the body attempts to expel the harmful substances. The rapid onset of nausea is a common response to the toxins affecting the digestive system.

Stomach flu

The stomach flu, or viral gastroenteritis, is an inflammation of the stomach and intestines caused by viruses. It leads to symptoms such as nausea, vomiting, diarrhea and stomach cramps. The body's immune response to the viral infection can trigger nausea as it tries to rid itself of the virus.

Brain injury

Nausea can also result from a brain injury, such as a concussion or traumatic brain injury (TBI). The brain’s control over nausea is influenced by various centers within it, and damage to these areas can disrupt normal functioning. As a result, individuals may experience nausea as a secondary effect of the injury.

Motion sickness

Motion sickness is caused by a conflict between the sensory signals received by the brain. When you are in motion, the inner ear, eyes and deeper body parts send conflicting messages, leading to symptoms such as dizziness and nausea. This is particularly common during travel by car, plane or boat.

Medications

Certain medications can also induce nausea as a side effect. Drugs such as antibiotics, chemotherapy agents and pain relievers may irritate the stomach lining or affect the brain's nausea centers, leading to feelings of queasiness.

Anxiety and stress

Emotional factors like anxiety and stress can manifest physically, including symptoms of nausea. The body's stress response can impact the digestive system, leading to an upset stomach and feelings of nausea, especially in high-pressure situations or during panic attacks.

How do allergies cause nausea?

According to the ACAAI, when an allergen is encountered, the immune system mistakenly identifies it as a threat and releases chemicals like histamines, which can irritate the stomach lining and stimulate the vagus nerve, triggering feelings of nausea. In cases of food allergies, the ingestion of allergenic foods can lead to inflammation in the digestive system, resulting in nausea and vomiting. Additionally, severe allergic reactions, such as anaphylaxis, can overwhelm the body and induce systemic responses that also contribute to gastrointestinal distress. Stress and anxiety related to experiencing an allergic reaction can further exacerbate nausea, highlighting the complex interplay between these factors.

How to treat nausea from allergies?

Treating nausea caused by allergies involves addressing the underlying allergic reaction and alleviating the symptoms. Here are several effective approaches according to the ACAAI:

Prescribed allergy medications

Antihistamines, such as cetirizine or loratadine, can help manage allergic reactions by blocking the effects of histamines released during an allergic response. These medications can reduce symptoms like nausea by alleviating the overall allergic reaction. Doctors may sometimes prescribe other medications, such as corticosteroids, to help reduce inflammation and provide relief.

Sublingual Immunotherapy

Sublingual immunotherapy involves placing a small dose of an allergen under the tongue to gradually build tolerance over time. This treatment can help reduce the severity of allergic reactions, including nausea, by desensitizing the immune system to specific allergens. It is a long-term solution that can lead to lasting relief from allergy symptoms.

Allergy shots

Allergy shots, or subcutaneous immunotherapy, involve receiving regular injections of allergens in increasing doses. This treatment aims to desensitize the immune system to specific allergens, thereby reducing the frequency and severity of allergic reactions, including nausea. Allergy shots typically require a commitment to a series of injections over several months or years.

Dietary management

For individuals with food allergies, strict avoidance of trigger foods is essential. Keeping a food diary can help identify and eliminate allergens from the diet, thereby preventing nausea and other allergic symptoms. Consulting with a nutritionist or allergist can provide guidance on managing food allergies effectively.

Over-the-counter antacids

Over-the-counter antacids may provide temporary relief for mild nausea associated with allergies. These medications can help soothe the stomach and reduce feelings of queasiness, although they do not address the underlying allergic response.

Hydration and rest

Staying hydrated and allowing the body to rest can also help mitigate nausea. Drinking clear fluids, such as water or herbal tea, can soothe the stomach and prevent dehydration, which may exacerbate feelings of nausea.

When to see a doctor?

While nausea from allergies can often be managed at home, certain signs indicate the need for medical attention. Here are some key symptoms to watch for according to the ACAAI:

Persistent nausea

If nausea persists for an extended period and does not improve with home remedies or over-the-counter medications, it’s important to seek medical advice. Persistent nausea could indicate a more serious underlying condition that requires evaluation.

Fever

The presence of a fever alongside nausea may signal an infection or a more severe allergic reaction. If the fever is high (typically above 101°F or 38.3°C) or lasts more than a couple of days, it’s essential to consult a healthcare professional for further assessment.

Vomiting blood

Vomiting blood, or hematemesis, is a serious symptom that requires immediate medical attention. This could indicate a severe reaction or gastrointestinal bleeding, both of which need urgent care.

Difficulty breathing

If nausea is accompanied by difficulty breathing, wheezing, or tightness in the chest, it could signify an anaphylactic reaction or severe asthma exacerbation. This situation is a medical emergency that requires immediate intervention.

Swelling of the face or throat

Swelling in the face, lips, tongue or throat, known as angioedema, can be a sign of a severe allergic reaction. If these symptoms occur alongside nausea, seek emergency medical help.

Severe abdominal pain

If nausea is accompanied by severe abdominal pain that does not subside, it may indicate a more serious gastrointestinal issue or a severe allergic reaction. This warrants a prompt evaluation by a healthcare provider.

Urgent care near me

If you’re experiencing persistent nausea or any concerning symptoms related to allergies, don’t wait to seek help. Take control of your health today using Solv to find urgent care near you.