Yeast Infection, or Something That Looks Like One

TL;DR: Itching is the biggest clue for yeast. A yeast infection usually brings thick white discharge, a lot of itching, and very little smell. A fishy or sweet smell points somewhere else, usually to bacterial vaginosis or to an infection called trichomoniasis. Burning when you pee, needing to go every few minutes, and pressure low in your belly point to a bladder infection instead. Yeast is treated with a pill called fluconazole, usually a single 150 mg dose. If the itching is severe, your doctor may add a second 150 mg dose 3 days later. A cream you put on the skin calms the itching while the pill does its work. Get checked before you treat if this is your first episode, if you are pregnant, if it keeps coming back, or if the treatment does not help within a few days. Guessing is easy to get wrong. When researchers examined women buying yeast treatment off the shelf, only about a third had yeast.

How do I know if this is a yeast infection?

Four questions sort out most of these, and they are the same 4 questions I ask on a message or a video visit before anything else happens.

The first is whether the main problem is itching. Vulvovaginal candidiasis, the medical name for a vaginal yeast infection, is an itching illness above all. When someone describes the itching as the thing keeping them awake or making it hard to sit through a meeting, yeast moves to the top of the list.

The second is whether the odor changed. Yeast does not usually produce a strong smell. A fishy odor, particularly one that gets stronger after sex, points toward bacterial vaginosis. A musty or sweet change also points away from yeast.

The third is what the discharge looks like. Yeast tends to produce thick white discharge, often described as looking like cottage cheese, which clings to the vaginal walls. Bacterial vaginosis produces a thin, gray-white discharge that coats the walls smoothly. Trichomoniasis classically produces a frothy yellow-green discharge, though the classic version shows up less often than textbooks suggest.

The fourth is whether there is burning with urination, urgency, frequency, or pressure low in the pelvis. Those belong to the bladder rather than the vagina. Women with yeast often do feel burning when urine passes over irritated vulvar skin, which is a different sensation from the deep internal burning of a bladder infection, and the distinction is worth teasing apart out loud.

One more marker helps in the office. Vaginal pH stays normal in yeast, around 4.0 to 4.5, while bacterial vaginosis and trichomoniasis both push it above 4.5. A pH strip and a look under the microscope answer in minutes what guesswork gets wrong more than half the time.

What else looks like a yeast infection?

Three conditions account for most of what turns out to be something other than yeast, and a fourth is not an infection at all.

Bacterial vaginosis is an overgrowth of the vagina's own bacteria after the protective lactobacilli thin out. The CDC diagnoses it clinically when 3 of 4 findings are present: thin gray-white discharge that coats the vaginal walls, vaginal pH above 4.5, a fishy odor when potassium hydroxide is added to a sample, and clue cells on microscopy. Itching is usually mild or absent, which is the practical separator from yeast. Treatment is metronidazole 500 mg orally 2 times a day for 7 days, metronidazole gel 0.75% intravaginally once a day for 5 days, or clindamycin cream 2% intravaginally at bedtime for 7 days. Antifungal treatment does nothing for it, which is why so many people treat themselves for a week with no improvement.

Trichomoniasis is an infection caused by a sexually transmitted parasite, Trichomonas vaginalis, and up to half of infections cause no symptoms at all. When it does cause symptoms, expect frothy yellow-green discharge, odor, irritation, and a pH above 4.5. The test that matters is a nucleic acid amplification test rather than a wet mount, since wet-mount microscopy has a sensitivity in the range of 44% to 68% and falls further if the slide sits before it is read. For women, the CDC recommends metronidazole 500 mg orally 2 times a day for 7 days, which halved the proportion of women still positive at 1 month compared with the older single 2 g dose in a randomized trial. Partners are treated, both people abstain until treatment is finished and symptoms are gone, and retesting at 3 months is standard because reinfection is common.

A urinary tract infection is the other frequent mix-up, since burning is the shared symptom. The distinguishing features are internal burning, urgency, frequency, blood in the urine, and suprapubic or back pain. In the JAMA rational clinical examination review, dysuria, frequency, hematuria, and back pain each raised the probability of a UTI, while a history of vaginal discharge (likelihood ratio 0.3) or vaginal irritation (likelihood ratio 0.2) lowered it substantially. Discharge and irritation count as evidence against a bladder infection, so they deserve a direct question rather than a skim past.

Irritation without any infection rounds out the list. New soap, a different laundry detergent, bath bombs, scented wipes, or shaving can inflame vulvar skin enough to produce itching and rawness that reads as yeast. Fragrances and botanical extracts in feminine hygiene wipes are among the most common contact allergens on that skin.

The scale of the mix-up is measurable. When 95 symptomatic women were examined right after buying an over-the-counter antifungal for what they believed was yeast, only about a third had yeast. Most of the rest had bacterial vaginosis, trichomoniasis, a mixed infection, or another genitourinary condition.

What does yellow or green discharge mean?

Color alone decides very little, and the pattern over time decides a lot.

A single episode of concentrated yellow or greenish discharge that is gone by the next bathroom visit, with no odor change and no itching, is usually concentrated normal discharge in someone who is under-hydrated. That pattern shows up in Philadelphia summers, on long travel days, and in people who train hard and drink less than they think. In my practice that one-off, self-resolving version has almost never turned out to be an infection.

Yellow-green discharge that persists across days, particularly alongside odor, irritation, or a new partner, is a different situation and deserves a trichomoniasis test. Trichomoniasis is easy to miss, easy to treat, and worth confirming rather than assuming, since it is also frequently silent in the partner who transmitted it.

What makes a yeast infection more likely right now?

The useful version of this question is what changed in the last few weeks, because yeast overgrowth almost always has a setup behind it.

Recent antibiotics are the most common trigger. A course for a sinus infection or a dental problem thins out the lactobacilli that keep Candida in check, and the yeast expands into the space.

Estrogen exposure raises the risk, which is why pregnancy, hormonal contraception, and hormone therapy all appear on the risk list. This does not mean stopping a contraceptive that works for you, though it does explain a new pattern that started when the pill did.

Diabetes that is not well controlled and any form of immunosuppression both make yeast more likely and harder to clear, and both move the episode from uncomplicated to complicated in the way clinicians classify it.

SGLT2 inhibitors deserve their own line. Empagliflozin and dapagliflozin work by making the kidney spill glucose into the urine, and that sugar feeds yeast on genital skin. Genital fungal infections run roughly 3 to 4 times more frequently on these drugs, and the effect holds across the whole class. This is usually manageable rather than a reason to stop a medication that is protecting your heart and kidneys, and it belongs in the conversation before the first prescription. Our full guide to SGLT2 inhibitors covers the trade-offs.

Local irritants and shaving matter more than most people expect. A new soap, a switched laundry detergent, bath products, scented wipes, and shaving all disturb the skin barrier. With shaving, the specifics change the answer: a blade against the grain with any nicks sets up folliculitis and raw skin, while an electric trimmer that leaves stubble rather than a bare surface causes far less trouble.

How is a vaginal yeast infection treated?

For an uncomplicated episode, meaning mild-to-moderate symptoms in someone without diabetes, pregnancy, or immunosuppression, the CDC regimen is fluconazole 150 mg orally as a single dose. Short courses of a topical azole, such as clotrimazole or miconazole for 1 to 7 days depending on the strength, work about as well and are the alternative for anyone who would rather avoid the oral drug.

When symptoms are severe, meaning extensive redness, swelling, excoriation, or fissures, a single dose is often not enough. The CDC regimen for severe disease is fluconazole 150 mg in 2 sequential oral doses, with the second dose 72 hours after the first, or 7 to 14 days of a topical azole. That 3-day repeat interval is the same rhythm used for recurrent disease, where the induction course is a 100 mg, 150 mg, or 200 mg dose of fluconazole every third day for 3 doses on days 1, 4, and 7.

A topical antifungal applied to the vulvar skin, with or without a low-potency steroid, is the piece that most often gets left out. The oral pill treats the infection while the itching continues for another day or 2, and a cream on the skin covers that gap. It is also the practical answer when someone is away from home and wants relief in the meantime.

Pregnancy changes the plan. Only topical azole therapy applied for 7 days is recommended during pregnancy. Oral fluconazole is avoided, since epidemiologic data have linked a single 150 mg dose to spontaneous abortion and congenital anomalies.

Non-albicans species change the plan too. Candida glabrata and its relatives respond poorly to fluconazole. The recommendation there is 7 to 14 days of a non-fluconazole azole, and for glabrata specifically, boric acid 600 mg in a gelatin capsule intravaginally once daily for 14 days. Boric acid is intravaginal only and is dangerous if swallowed, so it belongs in a labelled container away from anything you take by mouth.

What if it keeps coming back?

Recurrent vulvovaginal candidiasis means 3 or more symptomatic episodes in under a year, and it affects fewer than 5% of women. It is a specific diagnosis rather than a description, and it changes what happens next.

The first step is a culture with species identification, because repeated failure of fluconazole often turns out to be a non-albicans species or a resistant strain rather than an inadequate dose. Treating the wrong organism for a year is the more common story than treating the right one badly.

The second step is hunting for the driver: hemoglobin A1c if diabetes has never been ruled out, a look at repeated antibiotic courses, a review of SGLT2 inhibitors and other medications, and an honest inventory of soaps, detergents, wipes, and shaving habits.

The third step is the regimen itself. Induction with fluconazole every third day for 3 doses, then weekly maintenance dosing for 6 months, is what the CDC recommends. Relapse after maintenance stops is common enough that the plan should include what happens at month 7, rather than ending with the last pill.

What if this starts while I am travelling?

For someone with an established, confirmed pattern, carrying extra doses when going somewhere a clinician is hard to see is reasonable and something I set up regularly.

The travel kit that works is a dose or 2 of oral fluconazole plus a topical antifungal cream for the itching, with clear instructions on when to use the second dose and when to stop waiting and find care. Knowing you have a plan in your bag takes most of the dread out of a symptom starting on the first night of a trip.

The caveat matters as much as the kit. This approach fits someone whose episodes have been confirmed at least once, since self-treating an unconfirmed pattern is how bacterial vaginosis and trichomoniasis go untreated for weeks. If the doses in your bag do not work, that is information, and it should send you to a clinician rather than to a third dose.

When should I be seen instead of self-treating?

Some situations belong in front of a clinician rather than in front of a pharmacy shelf.

A first episode, since the diagnosis sets the pattern for every episode after it. Pregnancy, because the treatment differs. Symptoms that do not improve within a few days of treatment, or that come back within a month. Three or more episodes in a year. A new partner or a known STI exposure. Fever, pelvic pain, or back pain, which point beyond simple vaginitis. Persistent yellow-green discharge or a new odor. Blood in the urine with burning. Diabetes, immunosuppression, or an SGLT2 inhibitor in the medication list.

Fever with pelvic pain, or pain severe enough that you cannot stand up straight, is an urgent evaluation rather than a message that waits until morning.

Guidance from the Clinic

"Most of the diagnosis happens in the first 3 questions. Is the itching the loudest symptom, did the smell change, and is the burning on the outside or deep inside when you go. Those answers separate yeast from bacterial vaginosis from a bladder infection more reliably than the color of anything. Then I want to know what changed recently, because antibiotics, a new detergent, a razor, or a new diabetes medication explain a large share of what walks through the door, and treating the yeast without finding the setup means we meet again in 6 weeks."

Related at Fishtown Medicine

• SGLT2 Inhibitors: Heart, Kidney, and the Longevity Question - why this class causes genital yeast infections, and the trade-offs
• STI Testing in Philadelphia - what a full panel covers and when trichomoniasis testing is added
• UTI Treatment in Philadelphia - when burning belongs to the bladder and how it is handled same day
• Bladder Pain and Interstitial Cystitis - when the urine cultures keep coming back negative
• Women's Hormone Health - estrogen, the vaginal environment, and what changes with age
• Same-Day Sick Visits in Philadelphia - how acute problems are handled here

Scientific References

1. Centers for Disease Control and Prevention. "Vulvovaginal Candidiasis." Sexually Transmitted Infections Treatment Guidelines, 2021. CDC
2. Centers for Disease Control and Prevention. "Bacterial Vaginosis." Sexually Transmitted Infections Treatment Guidelines, 2021. CDC
3. Centers for Disease Control and Prevention. "Trichomoniasis." Sexually Transmitted Infections Treatment Guidelines, 2021. CDC
4. Nyirjesy P, Brookhart C, Lazenby G, Schwebke J, Sobel JD. "Vulvovaginal Candidiasis: A Review of the Evidence for the 2021 Centers for Disease Control and Prevention of Sexually Transmitted Infections Treatment Guidelines." Clinical Infectious Diseases. 2022;74(Suppl 2):S162-S168. PubMed
5. Ferris DG, Nyirjesy P, Sobel JD, Soper D, Pavletic A, Litaker MS. "Over-the-counter antifungal drug misuse associated with patient-diagnosed vulvovaginal candidiasis." Obstetrics and Gynecology. 2002;99(3):419-425. PubMed
6. Bent S, Nallamothu BK, Simel DL, Fihn SD, Saint S. "Does this woman have an acute uncomplicated urinary tract infection?" JAMA. 2002;287(20):2701-2710. PubMed
7. Kissinger P, Muzny CA, Mena LA, et al. "Single-dose versus 7-day-dose metronidazole for the treatment of trichomoniasis in women: an open-label, randomised controlled trial." Lancet Infectious Diseases. 2018;18(11):1251-1259. PubMed
8. Engelhardt K, Ferguson M, Rosselli JL. "Prevention and Management of Genital Mycotic Infections in the Setting of Sodium-Glucose Cotransporter 2 Inhibitors." Annals of Pharmacotherapy. 2021. PubMed