PID affects approximately 1 in 50 women annually in the UK — 25% of cases result in long-term sequelae (infertility, ectopic pregnancy, chronic pelvic pain) if inadequately treated. Chorioamnionitis is associated with 25% of preterm births and significant neonatal morbidity. Prepubertal vaginal discharge has different aetiology (physiological vs infection vs foreign body vs abuse) and requires a completely different approach — vaginal candidiasis is rare before puberty, and its presence in a child should prompt safeguarding consideration.

Clinical diagnosis of vaginal discharge is only 50–60% accurate based on history and examination alone — the "rule of three" (BV: fishy, thin, grey/white; Candida: itchy, thick, white; Trichomonas: frothy, yellow, itchy) helps but has significant overlap. BASHH guidelines recommend point-of-care testing where available. Pregnancy changes antibiotic choice significantly — metronidazole gel is acceptable in all trimesters but oral metronidazole is avoided in the first trimester where possible (teratogenicity concern, though risk is low).

Point-of-care testing (POCT) for vaginal pH is available via pH paper strips (simple, inexpensive) and has high clinical utility — BV and Trichomonas characteristically have pH >4.5 while Candida does not. Amsel criteria (clinical) remain valid for BV diagnosis in primary care without microscopy, with sensitivity ~90%. Mycoplasma genitalium is increasingly recognised as a cause of cervicitis and PID but is not routinely tested in primary care — consider referral to sexual health if persistent cervicitis despite standard STI treatment.

Cervical motion tenderness (CMT) on bimanual examination has 97% sensitivity for PID — it should be performed whenever PID is possible. The threshold for PID treatment should be low (BASHH 2019): clinical diagnosis is appropriate and delay risks tubal damage. Vulval inspection is frequently omitted but critical — lichen sclerosus, herpes, and primary syphilis may present with "discharge" symptoms but require entirely different management. Always offer and document chaperone.

Self-taken vulvovaginal NAAT swabs have equivalent sensitivity to clinician-taken endocervical swabs for chlamydia (96–99%) and gonorrhoea (>95%) — they remove the barrier of speculum examination, increasing uptake particularly in younger women. BASHH 2019 guidance recommends offering self-swabs. Gonorrhoea culture (not NAAT alone) is essential because antibiotic sensitivity testing is mandatory — multi-resistant gonorrhoea (MRNG) is increasingly prevalent in the UK, particularly following international travel. Never treat gonorrhoea empirically with azithromycin monotherapy — dual therapy is mandatory.

Gonorrhoea should be managed by sexual health services where possible — contact tracing, follow-up test of cure (TOC), sensitivity testing, and escalating resistance make specialist involvement preferable. BASHH 2019 states: all gonorrhoea cases should have culture taken before treatment for sensitivity testing. PID should have a low threshold for hospital admission: women who are pregnant, have suspected TOA, fail to respond to oral antibiotics in 72 hours, or have severe PID require IV antibiotics. Contact tracing (partner notification) is a legal and ethical obligation in STIs — sexual health services have specialist advisors to manage this.

BASHH updated gonorrhoea guidance in 2019 to remove routine azithromycin from dual therapy following evidence of increasing azithromycin resistance — ceftriaxone 1g IM monotherapy is now first-line for uncomplicated gonorrhoea where sensitivity testing is not yet available. PID empirical treatment must cover gonorrhoea, chlamydia, and anaerobes — using incomplete regimens (e.g. doxycycline alone) risks treatment failure and long-term sequelae. Vaginal lactic acid gel (pH 3.5–4.5) restores healthy vaginal microbiome in BV — evidence supports use as both treatment adjunct and suppressive therapy (Cochrane 2019).

Vaginal douching is the single most modifiable risk factor for recurrent BV — studies show women who douche have 2× higher BV prevalence. This advice is counterintuitive to many patients (who associate cleanliness with douching) and requires emphatic, non-judgmental communication. Partner treatment for trichomonas reduces re-infection rates from 36% to <10% — it is clinically essential, not optional. Glucose control in T2DM is the most effective single intervention for recurrent vulvovaginal candidiasis in diabetic women, often eliminating recurrence without long-term antifungal therapy.

Test of cure for gonorrhoea is mandatory — multi-drug resistant gonorrhoea (MDRNG) is increasing in the UK (PHE/UKHSA annual report shows increasing ceftriaxone MIC creep) and treatment failure must be identified promptly to prevent onward transmission. BASHH 2019 moved away from routine chlamydia TOC in uncomplicated cases because NAAT remains positive for up to 3 weeks post-treatment due to residual DNA — premature testing leads to false positives and unnecessary re-treatment. PID 72-hour review is evidence-based — clinical trials show 15% of outpatient PID cases require IV therapy escalation at 72 hours.