Sir, oral candidiasis (OC) is the most common opportunistic infection seen in patients infected with human immunodeficiency virus (HIV).1,2 Where OC does not respond to local measures and appropriate drug regimens, or there is no identifiable cause, this is when underlying causes such as HIV should be considered. This makes sexual history an essential part of the history taking process, and potentially a vital piece of the diagnostic puzzle. A recent case of a 70-year-old male who was referred by his GP to our oral and maxillofacial surgery (OMFS) department with refractory OC and was then later diagnosed with HIV has prompted this letter.

The authors do not advocate HIV testing for every patient who walks into the clinic with OC, but rather recommend that in cases of refractory OC, where appropriate, a sexual history be taken. This will prove vital to the clinician in deciding whether a referral to a specialist ie local OMFS department, or the patient's GP for further investigation is required.

Often there are social barriers to taking a sexual history which include time constraints, fear of patient embarrassment, fear of intrusion, insufficient training, age and sex of patient relative to that of the practitioner and cultural difference.3 Often, it is useful to pre-empt the patient's potential discomfort by initially informing them that they will be asked personal, and often embarrassing, questions.4

OC may be the first presentation of an occult disease,5 and still remains the second AIDS-defining illness in Europe. Therefore, in refractory cases or where there is no identifiable cause, dentists should use an appropriate sexual history combined with a thorough medical and social history. This plays a vital role in determining if HIV screening is necessary and overall provides the firm basis for gaining information regarding the patient's risk status in an environment where the patient is assured of the maintenance of privacy and confidentiality.