Candida (Candidiasis): Symptoms, Causes, and Treatment
Candida is a yeast (fungus) that lives naturally on the skin and inside the body. Candidiasis develops when the body's microbial balance is disrupted and Candida overgrows, causing infections ranging from oral thrush and vaginal yeast infections to invasive systemic disease.
Medically reviewed by Dr. Qiao Yufei, MD
This guide explains what causes candidiasis, how it spreads between partners, the symptoms by site, how it is diagnosed and treated, and how to reduce your risk. Although Candida is included in our broader STDs in Singapore overview because it is commonly checked alongside other genital infections, it is not strictly classed as a sexually transmitted infection.
What is candidiasis?
Candidiasis is an infection caused by the yeast (fungus) Candida. More than 20 species of Candida can cause infection in humans, with Candida albicans being the most common. Candida normally lives harmlessly on skin and in the mouth, throat, gut, and vagina, kept in check by other microorganisms.
Different sites produce different forms of infection: oral thrush (mouth and throat), vaginal candidiasis (yeast infection), cutaneous candidiasis (skin folds), and invasive candidiasis (a serious bloodstream and organ infection). According to the US Centers for Disease Control and Prevention (CDC), vaginal candidiasis is one of the most common reasons women see a doctor.
How candidiasis develops and spreads
Candidiasis develops when something disturbs the body's normal microbial balance, allowing Candida to multiply. It is primarily an overgrowth of yeast already present in the body, rather than a new infection caught from someone else.
Common contributors to overgrowth
- Antibiotic use that suppresses competing bacteria
- Weakened immune system from HIV/AIDS, cancer treatment, or organ transplant
- Poorly controlled diabetes, where elevated blood sugar feeds yeast
- Hormonal shifts, particularly during pregnancy or with certain contraceptives
- Excess moisture in skin folds, or persistently damp clothing
Can candidiasis spread between people?
Candida is not classified as a sexually transmitted infection in the strict sense, but it can be passed in some situations:
- Sexual partners: vaginal yeast infections can pass between partners through genital contact, although recurrence is more often due to repeat overgrowth than reinfection
- Mother to baby: a mother with vaginal candidiasis can pass the yeast to her baby during childbirth, causing oral thrush or diaper rash
- Close contact: sharing personal items such as towels or utensils can spread Candida, particularly to immunocompromised individuals
Symptoms of candidiasis
Symptoms vary by location. The four most common presentations are:
Oral thrush
White patches on tongue, inner cheeks, palate, gums, or tonsils. Soreness or redness in the mouth. Difficulty or discomfort swallowing.
Vaginal candidiasis (yeast infection)
Itching and irritation of the vagina and vulva. Thick, white, odourless discharge. Redness and swelling. Pain during intercourse or urination.
Cutaneous candidiasis
Red, itchy rash in moist warm areas: armpits, groin, under the breasts, between fingers and toes.
Invasive candidiasis
Fever and chills that do not improve with antibiotics. Can affect blood, heart, brain, eyes, and bones. More common in hospitalised or immunocompromised patients.
How candidiasis is diagnosed
Diagnosis depends on the affected site. At Mediway Medical Centre, the appropriate test is selected based on your symptoms and the area involved:
- Physical examination of the affected site (the most common starting point for skin or oral candidiasis)
- Microscopic examination of cell or swab samples to confirm yeast presence
- Fungal culture to identify the specific Candida species and guide antifungal choice
- Blood tests if invasive candidiasis is suspected, particularly in hospitalised or immunocompromised patients
How candidiasis is treated
Treatment depends on location and severity, and uses antifungal medication rather than antibiotics:
- Topical antifungals (creams, ointments, pessaries) such as clotrimazole or miconazole, for skin or vaginal infections
- Oral antifungals (fluconazole, itraconazole) for oral thrush or more extensive infections
- Intravenous antifungals (amphotericin B, echinocandins) for invasive candidiasis, administered in hospital
Most uncomplicated cases respond well to a short course of topical or oral antifungal therapy. Recurrent or treatment-resistant cases may need longer suppressive courses or culture-guided drug selection.
How to reduce your risk
- Keep skin dry and well-ventilated, particularly in moisture-prone areas (a real consideration in Singapore's tropical humidity)
- Manage underlying conditions such as diabetes carefully
- Avoid unnecessary antibiotic use; complete prescribed courses
- Wear loose, breathable cotton clothing and change out of damp clothes promptly
- Maintain a balanced diet to support immune function
- If you have recurrent vaginal candidiasis, treat partners simultaneously where appropriate to reduce ping-pong reinfection
What happens if candidiasis is left untreated?
Most uncomplicated candidiasis resolves with treatment, but untreated or undertreated infections can cause:
- Chronic or recurrent infections at the same site, which can become harder to treat over time
- Spread to other parts of the body, particularly in people with weakened immunity
- Invasive (systemic) candidiasis: the yeast enters the bloodstream and can affect the heart, brain, eyes, and bones. This form is rare in healthy people but life-threatening in immunocompromised patients and is one of the most common hospital-acquired bloodstream infections globally, per the CDC
- Neonatal thrush when passed from mother to baby during childbirth
If you have persistent oral patches, recurring vaginal symptoms, or unexplained fevers that do not respond to antibiotics, see a doctor for assessment.
Frequently asked questions
01 What is candidiasis, also called a Candida or yeast infection?
Candidiasis is the medical term for a Candida infection, commonly known as a yeast infection. It is a fungal infection caused by Candida species, most often Candida albicans. Candida normally lives in small amounts on the skin, in the mouth, gut, vagina, and skin folds. Infection occurs when Candida overgrows, often due to antibiotics, hormonal changes, diabetes, weakened immunity, or warm moist conditions.
02 What causes Candida infection?
Candida is normally kept in balance by the body's immune system and natural microbial flora. Infection develops when this balance is disrupted. Common triggers include antibiotic use (which reduces protective bacteria), pregnancy and hormonal changes, diabetes, weakened immunity (HIV, chemotherapy, corticosteroids), warm moist conditions, tight clothing, and skin irritation. Some people are more prone to recurrent infections.
03 What are the symptoms of a yeast infection?
Symptoms vary by location. Oral thrush: white patches on the tongue or inner cheeks, mouth soreness, difficulty swallowing. Vaginal yeast infection: itching, thick white odourless discharge, redness, pain during intercourse or urination. Skin-fold yeast infection: red itchy rashes in moist skin areas. Severe forms (rare): high fever and chills not responding to antibiotics, mainly in immunocompromised patients.
04 Is a yeast infection sexually transmitted?
A yeast infection is not typically classified as a sexually transmitted infection because Candida is part of the body's natural flora. People who do not have sex can still develop a yeast infection. However, it can sometimes be passed between sexual partners during intimate contact. Most vaginal yeast infections develop independently rather than from a partner. If a male partner develops symptoms (genital itching, redness), they should be checked and may benefit from treatment.
05 Can Candida infection be cured?
Yes. Candida infection is curable with appropriate antifungal treatment prescribed by a doctor. Most cases respond well to a short course of antifungal medication. Some people experience recurrent yeast infections, which may require longer or maintenance treatment. Identifying and addressing underlying triggers (such as uncontrolled diabetes or repeated antibiotic use) can help prevent recurrence.
06 How is Candida infection treated?
Candida infection is treated with antifungal medication. The type depends on where the infection is, symptom severity, pregnancy status, recurrence history, and whether other conditions need to be ruled out. Treatment may include creams, pessaries, lozenges, or oral medication. See a doctor if symptoms are new, recurrent, severe, or not improving.
07 How can I prevent yeast infections?
Yeast infection risk can be reduced by avoiding unnecessary antibiotics, maintaining good hygiene, wearing breathable cotton underwear and loose-fitting clothing, drying skin folds thoroughly, managing diabetes and blood sugar, avoiding douching or harsh soaps that disrupt vaginal flora, and changing out of damp swimwear or workout clothes promptly. For oral thrush, rinse the mouth after using inhaled steroids.
08 What happens if Candida infection is left untreated?
Most cases of Candida infection are not dangerous but may persist or recur if untreated. Untreated vaginal yeast infection can cause prolonged discomfort and may worsen in pregnancy. Untreated oral thrush may spread to the throat and oesophagus, causing painful swallowing. In immunocompromised individuals, untreated Candida infection can rarely spread to internal organs, which is a serious medical emergency requiring hospital treatment.
09 Why do yeast infections keep coming back?
Recurrent yeast infections may be linked to diabetes, repeated antibiotic use, pregnancy or hormonal changes, weakened immunity, irritation, or incomplete response to treatment. Some cases need testing to confirm Candida species and rule out other causes such as bacterial vaginosis (BV) or STIs. A doctor can recommend a longer treatment plan or investigate underlying triggers.
10 Where can I get tested or treated for Candida infection in Singapore?
You can be assessed at Mediway through a GP consultation. Diagnosis is often based on symptoms and examination, with swab or culture testing if symptoms are unclear, recurrent, severe, or not improving. The doctor will recommend treatment based on the type and location of infection. Speak to our team to arrange a confidential consultation.
Related conditions and next steps
References: CDC: About candidiasis · CDC: Invasive candidiasis · HealthHub Singapore
This page is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Consult a qualified healthcare professional for diagnosis and treatment of suspected candidiasis.