OVERVIEW

What is thrush?

Thrush is a common oral disease in children^[1]. It is caused by Candida albicans infection and is most commonly seen in newborns (from umbilical cord cutting to 28 days after birth) and infants (from 28 days after birth to the third year)^[1]. The main symptom is white membranous patches on the surface of the oral mucosa.

Mild infections may cause no obvious discomfort, but in severe cases, affected children may exhibit refusal to eat, restlessness, difficulty swallowing, and other discomfort reactions.

SYMPTOMS

What are the symptoms of oral thrush?

1. Oral thrush appears as milky-white patches on the oral mucosa, with normal surrounding skin, resembling milk residue. The patches may be dotted or merge into larger areas, appearing on the tongue, cheeks, palate, or inner lips.
2. Generally, there is no pain or discomfort, but some babies may experience increased drooling, mouth pain, and irritability due to concurrent stomatitis or angular cheilitis.
3. In severe cases, most or all of the oral mucosa may be covered by patches, which can spread to the throat, esophagus, trachea, or even lungs. If thrush spreads to the throat, it may affect swallowing or breathing and could be life-threatening.
4. Adults may experience dry mouth, mild throat pain, a burning sensation, or a feeling of obstruction, which worsens while eating^[2].

Can oral thrush cause fever?

Oral thrush usually does not cause fever (axillary temperature ≥ 37.5°C). However, if the condition is severe and spreads to the lower respiratory tract, fever may occur, typically accompanied by difficulty breathing or coughing—though this is rare.

Sometimes, oral thrush may coexist with respiratory or gastrointestinal infections, leading to symptoms like fever, cough, or diarrhea. Alternatively, thrush itself may arise due to weakened immunity from such infections, potentially causing fever along with other infection-related symptoms.

Can prolonged oral thrush lead to other diseases?

If oral thrush persists, babies may experience poor sleep, reduced food intake, and low mood due to discomfort, weakening their immunity and making them susceptible to other illnesses.

Recurrent or severe oral thrush may indicate underlying immune deficiency, increasing the risk of respiratory infections and other diseases.

CAUSES

What is Candida albicans in thrush patients?

Candida albicans, also known as Candida, is an opportunistic pathogen. This means it usually does not cause disease, but under certain conditions (such as malnutrition, prolonged use of broad-spectrum antibiotics, or glucocorticoid therapy like dexamethasone, prednisone, or methylprednisolone) that weaken the immune system, it can become pathogenic^[3].

Why do babies develop thrush?

1. Internal factors: After birth, various bacterial colonies gradually develop in a baby's mouth, maintaining a balanced ecosystem. Candida is part of the normal oral flora and typically harmless. However, factors like prolonged corticosteroid exposure in the mouth, poor oral hygiene, malnutrition, or weakened immunity can disrupt this balance, allowing Candida to overgrow and cause infection.
2. External infections: Contact with Candida-contaminated food, toys, clothing, or pacifiers. Newborns may acquire the infection during delivery (exposure to maternal vaginal fungi) or through unclean nipples during breastfeeding, contaminated caregiver hands, or improperly sanitized bottles or pacifiers.

Which immunodeficiency diseases may cause recurrent thrush in children?

Immunodeficiency disorders such as severe combined immunodeficiency (SCID) or chronic mucocutaneous candidiasis can lead to recurrent thrush.

However, parents should not immediately assume these conditions if their child has persistent thrush. Typically, immunodeficient children exhibit more severe symptoms like recurrent diarrhea, respiratory infections, or pneumonia alongside thrush.

If a child experiences recurrent diarrhea, pneumonia, or other illnesses accompanied by persistent or recurrent thrush, immunodeficiency should be considered. A professional diagnosis from a healthcare provider is essential, possibly including immunoglobulin testing for confirmation.

Can thrush be caused by asthma or nasal spray medications?

Not necessarily. Not all asthma or nasal sprays contain glucocorticoids.

Improper long-term use of steroid-containing asthma inhalers may lead to fungal infections in the mouth (thrush). To prevent this, rinsing the mouth after inhaler use is recommended to avoid prolonged steroid exposure. When used correctly, asthma inhalers rarely cause thrush.

Nasal sprays primarily act on the nasal passages and are unlikely to cause thrush.

DIAGNOSIS

What tests are needed for a baby with thrush?

1. Oral examination: Observe the extent and severity of mucosal damage in the oral cavity, and whether it is caused by milk residue, etc., to provide a basis for subsequent treatment.
2. Fungal examination: Collect samples from the oral mucosa and examine them under a microscope for the presence of Candida hyphae. If present, a diagnosis can be confirmed^[3].

If the baby's thrush recurs frequently, especially if accompanied by repeated fevers or respiratory infections, it is important to be alert to the possibility of immunodeficiency. In such cases, relevant tests such as a complete blood count or immunoglobulin levels may be conducted. However, this situation is relatively rare, as most babies with thrush have normal immunity. Therefore, immediate testing is not necessary upon recurrence, and examinations should be performed as required by the doctor.

How to distinguish thrush from milk residue?

Milk residue is usually easy to wipe off. After removing it with a cotton swab, the oral mucosa remains intact, smooth, and undamaged.
Thrush is difficult to wipe off. If forcibly removed, the oral mucosa may appear red, rough, and painful.

What is the difference between thrush and oral ulcers?

Thrush and oral ulcers are two different conditions. They can be distinguished in the following ways^[1,4]:

1. Affected population: Thrush is common in children and immunocompromised individuals; oral ulcers can occur in people of all ages.
2. Causes: Thrush is caused by Candida infection; oral ulcers may be related to psychological factors, bacterial infections, etc., and the exact cause is not entirely clear.
3. Symptoms: Thrush appears as white, membrane-like patches on the oral mucosa, usually causing no significant discomfort in children; oral ulcers exhibit typical "redness, yellow coating, depression, and pain," with a yellow-white membrane, a central depression, surrounding redness, and noticeable pain.
4. Treatment: Thrush requires antifungal medications such as nystatin or fluconazole; oral ulcers are treated symptomatically, such as with topical pain-relief medications like lidocaine or dyclonine.

What is the relationship between thrush and baby's milk crust?

Despite the word "crust" in its name, milk crust is not caused by a fungal infection and is entirely different from thrush. Milk crust is commonly seen in infants aged 1–3 months, with some improving after 4 months, hence its folk name "four-month crust." It is a type of eczema or dermatitis, often appearing on the face but can also occur elsewhere on the body.

Thrush primarily occurs inside the mouth and is caused by a fungal infection, differing from milk crust in both location and cause.

TREATMENT

Does a baby with thrush need to go to the hospital?

If the baby's thrush is mild, does not affect feeding, and the baby is in good spirits, you can observe at home for 2-3 days after removing possible causes (such as cleaning toys and bottles). If the thrush worsens—white patches in the mouth increase, or the baby becomes fussy, refuses to eat, or eats less—it is recommended to go to the hospital for further examination, diagnosis, and medication^[5].

Which doctor should be consulted for thrush?

Babies with thrush should see a pediatrician or neonatologist. Adults can visit the dental or oral medicine department.

What should be prepared before taking a baby with thrush to the doctor?

1. Baby’s medical history: When the thrush appeared, any accompanying symptoms (e.g., fever, cough, difficulty breathing), whether similar conditions occurred before, and any history of recurrent infections.
2. Baby’s personal information: Neonatal birth history (gestational age, delivery method, birth weight, etc.), allergy history, and medication contraindications.

When should a baby with thrush see a doctor immediately?

1. The baby repeatedly cries, refuses to eat, or appears lethargic.
2. The baby has a fever (armpit temperature ≥ 37.5°C), and/or symptoms like barking cough (a "hollow" cough resembling a dog's bark), difficulty breathing, or cyanosis (bluish skin or lips).

How is thrush treated? What medication is effective?

1. Nystatin is an antifungal medication highly effective against Candida albicans. It disrupts the fungus's metabolism, killing it. In China, nystatin suspension is not commercially available, so clinicians often crush nystatin tablets and mix them with cod liver oil to create a suspension for topical application (4 times daily for 7–14 days). Older children can use nystatin suspension as a mouth rinse (4 times daily). Nystatin is a prescription drug and must be purchased at licensed pharmacies or hospitals.

2. Oral antifungal medication: If the thrush is severe or topical treatment is ineffective, oral antifungals may be needed. Parents should consult a doctor before use and avoid self-medication. If thrush is widespread, recurrent, or unresponsive to local treatment, seek medical attention promptly and provide details of the condition and treatment history.

3. For recurrent thrush, identify underlying causes (e.g., prolonged antibiotic/steroid use, immune deficiency). Maintain proper diet and oral hygiene to prevent recurrence^[5].

What are the side effects of thrush medications?

The primary treatment, nystatin, is typically used topically as a suspension. It is not absorbed by mucous membranes or the gastrointestinal tract, so side effects are rare. High doses may cause digestive discomfort (e.g., diarrhea, nausea, vomiting), which resolves after dose reduction or discontinuation^[5].

How long does thrush take to heal?

Recovery time varies based on the child’s immunity and severity. Mild cases often improve within 3 days of treatment, while others may take 7–10 days.

How long should thrush medication be used?

Treatment typically lasts 1–2 weeks. Even if symptoms resolve in ~3 days, continue medication for another 3–7 days to prevent relapse from residual Candida.

What to do if thrush recurs?

1. Ensure proper medication adherence and complete the full course under medical guidance.
2. Identify and address possible causes (e.g., infected nipples, toys, or bottles). Maintain indoor humidity (50–60%) and temperature (24–25°C), with regular ventilation (20–30 minutes every 2–3 hours).
3. Encourage outdoor activities to boost immunity.
4. Provide a diet rich in vitamins and minerals (fruits/vegetables).
5. Avoid unnecessary antibiotics or steroids.
6. For immunocompromised babies, consider immune-boosting supplements (under medical advice). Most children with balanced diets do not need extra supplements.
7. If thrush recurs with frequent infections (respiratory, digestive, or skin), consult a doctor to rule out immune deficiencies (e.g., chronic mucocutaneous candidiasis).

Can probiotics treat thrush?

No. Probiotics improve gut flora and may synthesize vitamins/enzymes, but their efficacy for oral thrush is unproven. They are not recommended for thrush treatment.

DIET & LIFESTYLE

How to Care for a Baby with Thrush?

1. Mild thrush usually causes no discomfort. It is generally recommended to use a clean gauze soaked in saline or warm water to clean the baby's mouth before and after breastfeeding, and ensure adequate rest.

2. No dietary adjustments are needed; normal feeding is sufficient. If complications (such as stomatitis or angular cheilitis) occur or thrush worsens, symptoms like fever and pain may appear. In such cases, offer easily digestible liquid or semi-liquid foods, such as meat porridge, rice paste, or fruit/vegetable purees. After feeding, provide a small amount of water or clean the mouth with warm water.

3. A small number of babies may experience discomfort like fever or pain, leading to crying or irritability. Parents should remain calm and provide comfort. Distract the baby with play or reading. Maintain a clean, comfortable, and well-ventilated environment. Wash hands and clean toys regularly. Toys can be cleaned using the usual method or soaked/rinsed with a 2% sodium bicarbonate solution, which not only cleans but also eliminates Candida albicans.

4. If the baby refuses or significantly reduces food intake for an extended period, intravenous fluids may be necessary (in cases of mild fever, dry mucous membranes, cracked lips, sunken eyes, or other signs of dehydration) to replenish fluids and energy.

Is Thrush Contagious? If There Are Two Babies at Home and One Has Thrush, What Should Be Done for the Other Baby?

Thrush is not contagious. If one baby has thrush, the other does not need to be isolated. Ensure proper ventilation, clean toys, and wash hands before feeding. However, if the other baby has a history of recurrent thrush, it is best to avoid close contact temporarily.

PREVENTION

How to Prevent Thrush?

1. For newborns, pay attention to the cleanliness of pacifiers and nipples, and ensure caregivers wash their hands regularly (with water and detergent).

2. Keep living spaces well-ventilated and minimize air conditioning use in summer.

3. Allow babies to engage in appropriate outdoor activities and sun exposure (during mornings or evenings when UV rays are mild, for about 1 hour daily) to boost immunity.

4. Use antibiotics (anti-inflammatory drugs) rationally under a doctor's guidance and avoid indiscriminate use of such medications or hormones.

5. Supplement with vitamin B₂ and vitamin C appropriately to enhance immunity. Newborns should receive vitamin AD supplements starting 14 days after birth.

6. Expectant mothers should actively treat gynecological conditions (e.g., vaginal candidiasis) before delivery to prevent infant infection during birth^[1,2].

Can Zinc Supplementation Prevent Thrush in Babies?

Yes, for babies with zinc deficiency. Zinc is a vital trace element for immune function and plays a key role in skin and mucosal repair. Thrush in babies is usually mild and resolves well after addressing causative factors and using topical oral treatments, making additional zinc unnecessary.

If thrush recurs frequently, zinc deficiency should be considered. In such cases, zinc supplements at standard doses can aid recovery and prevent future episodes.

Do Babies with Thrush Need Frequent Cleaning or Sodium Bicarbonate Mouth Rinses to Prevent Infection?

No.

The body has strong self-regulating abilities, and resident oral bacteria maintain microbial balance, ensuring stability and reducing illness risk. Routine or occasional sodium bicarbonate rinses are unnecessary for thrush prevention, except in special cases (e.g., leukemia patients on chemotherapy, who may use saline rinses).

Can Disinfecting Toys and Clothes Prevent Thrush?

Yes. Before age 1, babies often chew toys or suck their hands. If toys or clothes carry Candida albicans, ingestion can lead to thrush. During this stage, clean toys and clothes regularly (using baby-safe detergents) to avoid oral transmission. Nursing hygiene is also crucial. While external factors matter, the baby’s immune status is more critical. Thus, strengthening immunity is key to disease resistance—"adapting to all changes by remaining unchanged."