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OTC casebook: Thrush


OTC casebook: Thrush

Alan Nathan looks at the treatment options for vulvo-vaginal candidiasis…




A young woman is referred to you by the medicines counter-assistant who says: “I think you had better deal with this one.”

You ask the woman how you can help and she replies: “All I asked for was tea tree oil for thrush ‘down below’ and your assistant said I had to speak to you. You do keep it in stock, don’t you?”

“Yes, we have it, but why tea tree oil?” you ask. “Have you used it before?”

“No, but I read about it today in Mail Online. It was recommended there.”

“How do you know you have thrush? Have you had it before?”

“No, but everyone knows the symptoms, don’t they?”

You ask the customer to describe her symptoms. She does so and they appear to be characteristic of vulvo-vaginal candidiasis (VC). You then ask if she has any other medical conditions. The woman replies: “Well I’m pregnant, if you call that a medical condition.”



1.     Is tea tree oil helpful in the treatment of vaginal thrush?

2.     What other ‘natural’ treatments or ‘home remedies’ are recommended for vulvo-vaginal candidiasis (VC)?

3.     What are the characteristic features of the condition?

4.     What are the factors that can predispose to VC?

5.     What conditions might be confused with VC and what are the distinguishing features?

6.     What are the circumstances and factors for referring a patient requesting treatment for VC to their doctor?

7.     What OTC treatments are available to treat VC?

8.     How might you have dealt with this customer?



1.     A BMJ clinical evidence review in 2013 on the treatment of vulvo-vaginal candidiasis found no clinical trials involving intravaginal tea tree oil. However, it found one systematic review that stated that topical tea tree oil can cause skin irritation and a severe allergic rash, plus a case report that found that it was associated with systemic hypersensitivity reaction. However, there are several websites that recommend its use.


2.     Many ‘natural’ treatments and remedies are recommended for treatment of thrush. Those for which some evidence of efficacy against candida infection has been presented include aloe vera, apple cider vinegar, baking soda, boric acid, coconut oil, garlic, oregano oil and yogurt.


3.     The characteristic symptoms of VC are irritation or itching in the vulvovaginal area, which is often intense and burning. The external skin may be excoriated and raw from scratching.

There may be vaginal discharge, either creamy-coloured, thick and curdy in appearance, or thin and rather watery but with no offensive odour.

There may be stinging on passing water due to inflammation of the vulva but otherwise no pain and there is no increased frequency or urgency of micturition. The vulva may be reddened and swollen.


4.     Predisposing factors for VC are:

·      Pregnancy

·      Diabetes

·      Broad-spectrum antibiotics

·      Immunocompromised status

·      Immunosuppressant drugs, including oral steroids

·      Use of bath additives, vaginal deodorants and preparations for vulval pruritus containing local anaesthetics

·      Wearing occlusive underwear.


5.     Conditions that might be confused with VC include:

Bacterial vaginosis: vaginitis (vaginal inflammation) caused by a combination of bacterial species usually present at low counts in the vagina, which when present at higher levels disrupt the normal flora and cause infection. Discharge may be confused with thrush, but it is white and watery with a strong ‘fishy’ odour. Itching is a less prominent feature than in candidiasis.

Trichomoniasis: a sexually transmitted disease caused by a protozoan parasite, Trichomonas vaginalis. As in thrush, there is vulvar itching, but discharge is profuse, frothy, yellow-green in colour and with an unpleasant odour.

Cystitis: with thrush, discomfort when urinating may be confused with dysuria associated with cystitis. However, in thrush the discomfort and burning are in the external vaginal area rather than in the bladder and urethra as in cystitis.

Atrophic vaginitis: in postmenopausal women a lack of oestrogen reduces vaginal resistance to infection and injury, which can produce similar burning and itching symptoms to thrush, but thrush is uncommon in postmenopausal women.

Adverse drug reactions: drugs that can predispose to thrush include broad-spectrum antibiotics, corticosteroids and drugs that can affect oestrogen levels, including oral contraceptives, hormone replacement therapy, tamoxifen and raloxifene.


6.     Red flags - symptoms and circumstances for referral to a GP:

·      If vaginal candidiasis has not been previously diagnosed by a doctor: there are other vaginal infections, some serious and all requiring treatment with prescription-only medication, with symptoms that could be confused with thrush.

An initial medical diagnosis of candidiasis is necessary so that sufferers can recognise the condition subsequently.

·      Patients with recurrent attacks: more than two within the previous six months may indicate an underlying cause such as diabetes.

·      Patients under 16 or over 60 years of age: thrush is rare in these age groups due to the lack of vaginal oestrogen, which favours growth of C. albicans, but lack of oestrogen increases susceptibility to other vaginal infections. OTC treatments are not licensed for use in these groups.

·      Pregnant or breastfeeding women: OTC treatments are not licensed for use in these patients.

·      Abnormal or irregular vaginal bleeding.

·      Any blood staining of vaginal discharge.

·      Vulval or vaginal sores, ulcers or blisters.

·      Lower abdominal pain or dysuria, which may indicate a urinary tract infection.

·      Patients with a previous history of sexually transmitted disease or exposure to a partner with such a history, as other infections may be present.

·      No improvement after treatment with OTC medication.


7.     OTC treatments for vaginal candidiasis include the azoles, fluconazole and clotrimazole. Azoles are synthetic antimycotic agents that act by inhibiting replication of yeast cells through interfering with the synthesis of ergosterol, the main sterol in the yeast cell membrane.

Fluconazole is presented as a single-dose 150mg oral capsule. It is well absorbed when taken by mouth and symptoms usually improve within 12 to 24 hours following administration. Adverse effects are generally mild and mainly gastrointestinal, including abdominal pain, diarrhoea, nausea and vomiting and flatulence.

Fluconazole interacts with a number of drugs, including those metabolised by cytochrome P450 isoenzymes CYP3A4 and CYP2C9, but interactions are unlikely to be clinically significant with a single dose of fluconazole. Nevertheless, caution should be exercised with patients taking drugs that have both a narrow therapeutic window and also act on vital organ systems such as the heart and brain, or are involved with glucose metabolism.

Clotrimazole is only used topically because of adverse effects when given orally and varying absorption rates, and because it is metabolised in the liver to inactive compounds. It is available for intravaginal use as a single 500mg pessary, a 5g prefilled single application of 10% cream and as 2% cream available for twice or three times daily application to the external genitalia.

Symptoms usually begin to improve more quickly than with oral fluconazole. The bases used in preparations may damage latex condoms and diaphragms.

Night-time use is recommended for intravaginal preparations as the patient will be lying down for several hours, allowing the drug a chance to act and avoiding the problems of seepage and loss that would occur if the patient was upright and moving around.


8.  The pharmacist’s advice

You should advise the woman not to use any tea tree oil preparation as it is considered to be potentially harmful in pregnancy.

You advise that the symptoms she described certainly appeared to be thrush and that while there were effective treatments available without prescription, she ought to contact her doctor or her antenatal clinic to get the diagnosis confirmed. Also, as she is pregnant she should not take the oral fluconazole.









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