Vulval swelling

Vulval swelling is enlargement of one or both labia, the vestibule, the clitoris or the perineum, which may be localised (lump, cyst, abscess) or diffuse (oedema). Most localised swellings are Bartholin gland cysts or abscesses, epidermoid cysts and folliculitis, while diffuse swelling usually reflects oedema, cellulitis, allergic or irritant reaction. The main clinical point is to identify necrotising infection, haematoma, malignancy and hernia, and to find the systemic cause of diffuse oedema.

Clinical relevance. Necrotising infection of the vulva and perineum is a surgical emergency with high mortality, and vulval cancer is often delayed because lesions are mistaken for benign disease.

Anatomy. The vulva comprises the mons, labia majora and minora, clitoris, vestibule, urethral meatus, Skene glands, Bartholin glands, hymen and perineum. The round ligament enters the labium majus through the inguinal canal, with a possible peritoneal pouch (canal of Nuck).

Mechanisms. Swelling results from duct obstruction, infection, haemorrhage, lymphatic or venous obstruction, fluid retention, vascular permeability, herniation and new tissue growth (benign or malignant).

Classification. By onset: acute (hours to days) or chronic (weeks to years). By distribution: unilateral or bilateral. By nature: cystic, solid, diffuse oedema, vascular, or reducible. By cause: infective, traumatic, systemic, inflammatory, neoplastic or congenital.

Key distinctions. A tender posterolateral fluctuant swelling at the introitus is a Bartholin abscess. A painless unilateral, reducible mass that enlarges with straining is a hernia or hydrocele of the canal of Nuck. Pitting oedema affects both labia in systemic fluid retention. Sudden painful swelling after trauma or delivery is a haematoma.

History

• Onset (sudden or gradual), duration, size change, pain, itching, burning, discharge, ulcer, bleeding.
• Fever, rigors, malaise, spreading redness (cellulitis, abscess, necrotising infection).
• Trauma, straddle injury, recent delivery, episiotomy, intercourse injury, sexual assault, genital cutting or piercing, shaving or waxing.
• Pregnancy, parity, postpartum status; leg swelling, headache or visual symptoms (pre eclampsia).
• Sexual history, new partners, sexually transmitted infection, genital ulcers, groin lumps.
• Skin disease: lichen sclerosus, hidradenitis suppurativa, eczema, psoriasis, Crohn disease.
• Drugs: ACE inhibitors, calcium channel blockers, NSAIDs, thiazolidinediones, new topical products, latex, antibiotics, anticoagulants, SGLT2 inhibitors (genital infection and Fournier gangrene).
• Medical: diabetes, heart failure, nephrotic syndrome, liver disease, malnutrition, immunosuppression, HIV, lymphatic filariasis in endemic regions, obesity, previous radiotherapy or lymph node surgery.
• Hereditary or recurrent angioedema, urticaria, allergic reactions.
• Cancer risk: smoking, HPV, lichen sclerosus, immunosuppression, previous vulval intraepithelial neoplasia.

Examination

• Vital signs, hydration, signs of sepsis; abdomen, groin lymph nodes, legs (oedema).
• Inspect with good light: size, colour, symmetry, skin changes, ulcer, pigmentation, warts, erosion, scars, discharge.
• Palpate between thumb and finger: cystic, solid, warm, tender, fluctuant, fixed to skin, reducible, impulse on coughing, transillumination.
• Location: posterolateral introitus (Bartholin), periurethral (Skene), mons, labium majus (hernia, canal of Nuck), clitoris, perineum.
• Crepitus, skin necrosis, blistering, purple discolouration, severe pain out of proportion (necrotising infection).
• Speculum and bimanual examination when tolerated; urine dipstick.
• Examination under anaesthesia in girls or when pain prevents examination.

Red flags

• Fever, tachycardia, hypotension or severe pain out of proportion to appearance, skin discolouration, crepitus or bullae (necrotising fasciitis, Fournier gangrene).
• Rapidly expanding swelling with pallor or falling haemoglobin (large haematoma).
• Irreducible, tender or discoloured groin swelling (strangulated hernia).
• Ulcer, fixed mass, pigmented or irregular lesion, bleeding, groin node enlargement (malignancy).
• Swelling with airway, facial or tongue swelling (angioedema).
• Diabetes, immunosuppression or SGLT2 inhibitor use with vulval pain.
• Pre eclampsia features with oedema.
• A new Bartholin mass in a woman over 40, or a recurrent mass.
• Suspected sexual assault or non accidental injury in a child.

Special groups. Pregnancy: varicosities, oedema and pre eclampsia. Postpartum: haematoma, infection, perineal oedema. Girls: labial adhesions, urethral prolapse, haemangioma, rhabdomyosarcoma and abuse. Postmenopausal: lichen sclerosus, vulval intraepithelial neoplasia and cancer.

Organised by nature of swelling. Each cause is common unless marked serious or uncommon. Cystic or localised infective swellings

• Bartholin duct cyst or abscess.
• Skene duct cyst or abscess, paraurethral cyst.
• Epidermoid (sebaceous) cyst, Fox Fordyce spots, mucous cyst of the vestibule.
• Folliculitis, furuncle, carbuncle, vulval abscess.
• Hidradenitis suppurativa.
• Pilonidal or perianal abscess extending to the vulva.
• Vulval Crohn disease.
• Cyst of the canal of Nuck (hydrocele of the round ligament).
• Hidradenoma papilliferum.

Diffuse swelling and oedema

• Vulval cellulitis or erysipelas.
• Vulval oedema of pregnancy, pre eclampsia, nephrotic syndrome, heart failure, hypoalbuminaemia, liver disease, ovarian hyperstimulation, ascites.
• Lymphoedema (post surgical, post radiotherapy, inflammatory, lymphatic filariasis, tuberculosis).
• Allergic or irritant contact dermatitis.
• Angioedema (ACE inhibitor related, hereditary, allergic).
• Candida vulvovaginitis with oedema; herpes simplex with oedema.
• Lichen sclerosus (oedema, fusion), vulval Crohn disease.
• Hereditary or acquired C1 inhibitor deficiency.
• Serious: necrotising fasciitis (polymicrobial or group A streptococcus) and Fournier gangrene.
• Hair tourniquet in infants.

Vascular and traumatic

• Vulval haematoma (obstetric, straddle injury, sexual assault, surgery).
• Vulval varicosities (pregnancy, pelvic congestion).
• Haemangioma and lymphangioma.

Hernia

• Inguinal hernia, femoral hernia, hydrocele of the canal of Nuck.
• Labial hernia with bowel (serious if strangulated).
• Endometriosis of the round ligament or the canal of Nuck.

Infectious, sexually transmitted and tropical

• Genital warts (condylomata acuminata), molluscum contagiosum.
• Primary syphilis chancre and condylomata lata.
• Lymphogranuloma venereum with inguinal buboes, donovanosis, chancroid.
• Genital herpes, scabies nodules, pediculosis pubis, tungiasis.
• Lymphatic filariasis (vulval elephantiasis), schistosomal granuloma, genital tuberculosis (uncommon).
• Mpox lesions (uncommon).

Benign and malignant tumours

• Lipoma, fibroma, leiomyoma, neurofibroma, granular cell tumour, accessory breast tissue.
• Seborrhoeic keratosis and naevus.
• Serious: vulval intraepithelial neoplasia, squamous cell carcinoma, melanoma, Bartholin gland carcinoma, basal cell carcinoma, extramammary Paget disease, sarcoma, lymphoma, vulval metastasis.

Congenital and anatomical

• Clitoromegaly (congenital adrenal hyperplasia, androgen excess, androgen secreting tumour, drugs), clitoral cysts.
• Labial hypertrophy, labial adhesions, ectopic urethra, urethral prolapse.
• Scarring and keloid after female genital cutting, inclusion cyst and neuroma.
• Imperforate hymen with mucocolpos or haematocolpos.

Stepwise reasoning

1. Decide whether the swelling is localised or diffuse, painful or painless, and unilateral or bilateral.
2. Look for sepsis, necrotising infection, haematoma and strangulated hernia, which need the same day action.
3. Test for infection and pregnancy; screen for systemic causes of oedema when swelling is diffuse.
4. Image deep or unclear swellings.
5. Biopsy any persistent, atypical or pigmented lesion, and any Bartholin mass in a woman over 40.

First line tests

• Vital signs, capillary glucose or HbA1c, urine dipstick and pregnancy test.
• Full blood count, C reactive protein, urea, creatinine, electrolytes, lactate (when sepsis is suspected), blood cultures.
• Swab of pus for Gram stain and culture, including Staphylococcus aureus (test for methicillin resistant strains), anaerobes and group A streptococcus.
• Nucleic acid amplification tests for chlamydia, gonorrhoea, Trichomonas vaginalis and Mycoplasma genitalium; herpes simplex virus PCR from lesion; syphilis serology; HIV, hepatitis B and C tests.
• For diffuse oedema: albumin, urinary protein creatinine ratio, liver function tests, thyroid function, brain natriuretic peptide; C4 (low in most hereditary and acquired angioedema), C1 inhibitor level and function when angioedema is recurrent without urticaria.
• Wet mount and Gram stain for candida.

Imaging and procedures

• Ultrasound of the vulva and groin: cyst or solid mass, hernia sac, abscess, haematoma, vascular structure with Doppler.
• CT of the pelvis with intravenous contrast for suspected necrotising infection (gas in the tissue) or deep abscess, without delaying surgery; clinical diagnosis is sufficient for emergency debridement.
• MRI pelvis for large, deep, atypical or recurrent masses, haemangioma, endometriosis and tumour staging.
• Biopsy: punch or excisional biopsy of ulcers, plaques, warts that do not respond to treatment, pigmented lesions (excision with margins), and persistent Bartholin masses in women over 40. Cystic masses that recur need excision and histology.
• Culture or cytology for lymphogranuloma venereum (nucleic acid test of ulcer or bubo aspirate), donovanosis (smear for Donovan bodies), tungiasis (flea), microfilariae on night blood film or antigen test in endemic regions.
• Pelvic and renal ultrasound for adolescents with suspected obstructed anomaly.
• Hormone testing (17 hydroxyprogesterone, testosterone, dehydroepiandrosterone sulphate) for clitoral enlargement.

Limitations. Bartholin cultures often grow mixed flora, so a negative culture does not exclude infection. Necrotising infection cannot be excluded by imaging, and early signs may be subtle. Ultrasound cannot separate cyst from solid malignancy in all cases. Biopsy of a necrotic lesion may be non diagnostic.

Immediate steps. Assess airway, breathing and circulation. Treat shock with intravenous crystalloid in 250 to 500 mL aliquots and early antibiotics. Obtain senior surgical and gynaecological assessment for suspected necrotising infection, large haematoma, strangulated hernia or airway involvement.

Analgesia.

• Paracetamol 1 g orally every 4 to 6 hours, maximum 4 g daily (3 g daily with chronic alcohol use, malnutrition or hepatic impairment; 15 mg/kg each dose under 50 kg)
• Ibuprofen 400 mg orally every 6 to 8 hours with food, maximum 2.4 g daily. Avoid in peptic ulcer, renal impairment, heart failure and NSAID sensitive asthma. Avoid in suspected necrotising infection, as it can mask progression

Bartholin cyst or abscess.

• Asymptomatic cysts: observe
• Symptomatic cyst or abscess: incision and drainage with an inflatable tip catheter placed for 4 to 6 weeks, or marsupialisation. Use local anaesthetic (lidocaine 1% 2 to 5 mL; maximum 200 mg of plain lidocaine, 3 mg/kg) or general anaesthesia. Advise warm baths twice daily
• Antibiotics only for cellulitis, systemic illness, immunosuppression or sexually transmitted infection risk: co-amoxiclav 625 mg orally three times daily for 5 to 7 days (625 mg twice daily when creatinine clearance is under 30 mL/min)
• Penicillin allergy: doxycycline 100 mg orally twice daily with metronidazole 400 mg orally twice daily for 5 to 7 days. Avoid doxycycline in pregnancy; use clindamycin 300 mg orally four times daily
• Treat gonorrhoea or chlamydia if detected (ceftriaxone 1 g intramuscularly once and doxycycline 100 mg orally twice daily for 7 days)
• Recurrent abscess: marsupialisation or gland excision. Biopsy persistent masses in women over 40

Other abscess, folliculitis and cellulitis.

• Drain abscesses
• Flucloxacillin 500 mg to 1 g orally four times daily for 5 to 7 days for cellulitis or folliculitis with spreading erythema (maximum 4 g daily; adjust for creatinine clearance under 10 mL/min)
• Penicillin allergy: clarithromycin 500 mg orally twice daily for 5 to 7 days (check interactions)
• Methicillin resistant Staphylococcus aureus: doxycycline 100 mg orally twice daily or co-trimoxazole 960 mg orally twice daily. Avoid co-trimoxazole in pregnancy, creatinine clearance under 15 mL/min and sulphonamide allergy

Necrotising fasciitis and Fournier gangrene. Emergency debridement within hours, with intravenous broad spectrum antibiotics:

• Piperacillin with tazobactam 4.5 g intravenously every 6 to 8 hours (adjust for renal function)
• Plus clindamycin 600 to 900 mg intravenously every 8 hours (toxin suppression)
• With vancomycin 15 to 20 mg/kg intravenously every 8 to 12 hours (adjusted to levels) if methicillin resistant organisms are likely

Give fluids, vasopressors as needed, intensive care, repeat debridement at 24 to 48 hours, and glycaemic control. Stop SGLT2 inhibitors.

Haematoma. Small, stable haematoma: ice packs for 24 hours, analgesia and observation.

Expanding haematoma, severe pain or retention: incision with evacuation and ligation of the bleeding vessel, or interventional embolisation, with catheterisation, transfusion as needed, and antibiotics. Monitor pulse, blood pressure and haemoglobin.

Oedema. Treat the cause: diuretics for heart failure, albumin and protein replacement for hypoalbuminaemia, delivery and magnesium sulphate for severe pre eclampsia, and compression garments with skin care for lymphoedema. Pregnancy related oedema usually settles with elevation of the legs and rest.

Angioedema. Stop ACE inhibitors permanently.

• Allergic angioedema: adrenaline 0.5 mg (0.5 mL of 1 in 1000) intramuscularly into the anterolateral thigh for airway involvement, repeated every 5 minutes. Give chlorphenamine 10 mg intravenously or orally and hydrocortisone 200 mg intravenously
• Hereditary angioedema: icatibant 30 mg subcutaneously, repeated after 6 hours (maximum 3 doses in 24 hours), or C1 esterase inhibitor 20 units/kg intravenously. Antihistamines, corticosteroids and adrenaline are not effective. Specialist immunology care for prophylaxis

Infections and sexually transmitted infections.

• Primary or early syphilis: benzathine benzylpenicillin 2.4 million units intramuscularly as a single dose (doxycycline 100 mg orally twice daily for 14 days if allergic and not pregnant)
• Genital herpes: aciclovir 400 mg orally three times daily for 5 days for a first episode (extended to 7 to 10 days if new lesions continue; adjust to creatinine clearance under 25 mL/min), or valaciclovir 500 mg orally twice daily for 5 days
• Lymphogranuloma venereum: doxycycline 100 mg orally twice daily for 21 days
• Donovanosis: azithromycin 1 g orally weekly, or 500 mg daily, for at least 3 weeks and until lesions heal
• Chancroid: azithromycin 1 g orally single dose or ceftriaxone 250 mg intramuscularly single dose
• Genital warts: cryotherapy, trichloroacetic acid 80 to 90% weekly, podophyllotoxin 0.5% solution applied twice daily for 3 days then stopped for 4 days, repeated for up to 4 cycles (external warts only, not in pregnancy), or imiquimod 5% cream applied 3 times weekly for up to 16 weeks and washed off after 6 to 10 hours
• Molluscum: observe, or curettage or cryotherapy
• Treat partners and test for other infections

Lymphatic filariasis. Specialist treatment: albendazole 400 mg orally as a single dose with ivermectin 200 microgram/kg orally as a single dose (or diethylcarbamazine 6 mg/kg single dose). Exclude loiasis and onchocerciasis first because of severe reactions. Limb and vulval hygiene, skin care and compression for lymphoedema.

Hidradenitis suppurativa. Wash with antiseptic, wear loose clothing, weight loss and smoking cessation. Topical clindamycin 1% solution twice daily for 12 weeks. Doxycycline 100 mg orally twice daily for 12 weeks for moderate disease. Specialist treatment for severe disease (biological agents, surgery).

Hernia and canal of Nuck cyst. Surgical repair. Emergency surgery for strangulation.

Neoplasms. Biopsy and refer within 2 weeks to gynaecological oncology. Vulval intraepithelial neoplasia: wide local excision, laser ablation or topical therapy. Invasive cancer: wide local excision with groin lymph node assessment (sentinel node biopsy or lymphadenectomy), with chemoradiation for advanced disease.

Clitoral enlargement. Urgent endocrine and paediatric assessment for congenital adrenal hyperplasia; hydrocortisone replacement by specialists.

Special groups.

• Pregnancy: drain abscesses, avoid podophyllotoxin, imiquimod and doxycycline, treat cellulitis with flucloxacillin or clindamycin, and manage pre eclampsia
• Girls: gentle oestrogen cream 0.01% daily for 2 to 4 weeks for labial adhesions. Treat urethral prolapse with topical oestrogen cream or surgery. Assess for child protection when abuse is suspected
• Diabetes: tight glycaemic control and low threshold for admission

Monitoring. Review catheter and wound at 1 week and 4 to 6 weeks. Monitor temperature, pulse, blood pressure, haemoglobin, creatinine and glucose in admitted women. Follow biopsy results within 2 weeks.

Referral and escalation. Refer the same day to the on call gynaecology and surgical teams for suspected necrotising infection, expanding haematoma, strangulated hernia or airway involvement.

Refer within 2 weeks for suspected cancer. Refer to dermatology, genitourinary medicine, immunology, paediatrics or urology as the findings direct.

Admission criteria. Sepsis, necrotising infection, large haematoma, airway involvement, uncontrolled pain, inability to void, diabetic decompensation, strangulated hernia, and failure of outpatient drainage.

Discharge and follow up. Most localised swellings are managed as outpatients. Provide written wound care, analgesia and review dates.

Safety netting. Return for fever, spreading redness, increasing pain, blistering, dark skin, bleeding, swelling that returns after drainage, difficulty breathing or swallowing, or inability to pass urine.