Unexplained localised swelling

Unexplained localised swelling is an increase in the size of a defined body region, part or structure (a lump, a swollen limb, a swollen joint, a swollen face) for which no cause is evident at first contact. Examples are a soft tissue mass, lymph node enlargement, a swollen limb (oedema, deep vein thrombosis, lymphoedema), a swollen joint, scrotal swelling, a breast lump, a thyroid swelling, and swelling of the face, tongue or lips.

The key questions are whether the swelling is inflammatory, vascular, neoplastic, traumatic, cystic, hernial or allergic, and whether it is time critical (compartment syndrome, necrotising infection, airway angioedema, testicular torsion, strangulated hernia, limb threatening ischaemia).

Clinical relevance. Most lumps are benign (lipomas, cysts, reactive nodes), but malignancy, infection with systemic toxicity and vascular emergencies must be excluded quickly. A lump larger than 5 cm, deep to the fascia, growing, or painful and hard has a significant chance of being a sarcoma.

Classification by tissue.

• Skin and subcutaneous: epidermoid cyst, lipoma, abscess, cellulitis, ganglion, dermatofibroma, haematoma, cutaneous malignancy, hidradenitis.
• Lymph node and lymphatic: reactive nodes, infection, lymphoma, metastasis, lymphoedema.
• Vascular: deep vein thrombosis, superficial thrombophlebitis, aneurysm, haemangioma, varicocele, arteriovenous malformation.
• Glandular: thyroid, salivary, breast, parotid, Bartholin gland.
• Muscle and soft tissue: sarcoma, haematoma, abscess, myositis ossificans, compartment syndrome.
• Bone and joint: fracture, bone tumour, osteomyelitis, arthritis, effusion, bursitis.
• Hernia and visceral: inguinal, femoral, umbilical, incisional, epigastric hernias, organomegaly.
• Allergic and angioedema: histaminergic, bradykinin mediated.

Classification by time course. Acute (hours to days: infection, trauma, thrombosis, angioedema, torsion), subacute (weeks: abscess, infective lymphadenitis, tuberculosis, lymphoma), chronic (months: benign tumour, cyst, lipoma, malignancy).

History.

• Site, size, onset, duration, change with time, rate of growth, pain, tenderness, colour change, discharge, relationship to meals (salivary), to posture, to cough or straining (hernia), and to exertion.
• Systemic symptoms: fever, night sweats, weight loss, fatigue, itching, anorexia, breathlessness, cough, bone pain.
• Trauma, bites, injection, insect or animal contact, foreign body, recent surgery or procedure, immobilisation, long travel.
• Skin or mucosal infection near the lump, dental problems, sore throat, genital symptoms, sexually transmitted infection, tuberculosis contact, HIV risk.
• Allergen exposure, new drug (ACE inhibitors, NSAIDs, antibiotics), food, family history of angioedema.
• Past history: cancer, bleeding disorder, anticoagulation, heart, liver or kidney disease, thyroid disease, lymphoedema, previous radiation or lymph node surgery.
• Travel to endemic areas (filariasis, onchocerciasis, schistosomiasis, tuberculosis, trypanosomiasis).
• Family history of lumps, cancer, hereditary angioedema.

Examination.

• General: vital signs, appearance, hydration, pallor, jaundice, generalised lymph nodes, spleen, liver.
• The swelling: site, size (measure with ruler or calipers), shape, surface, edge, consistency (soft, firm, hard, rubbery, fluctuant), tenderness, warmth, colour, mobility and attachment to skin and deeper structures.
• The swelling, further features: pulsatility, thrill or bruit, transillumination, reducibility, cough impulse, compressibility, relationship to adjacent structures, and regional lymph nodes.
• Limbs: pitting versus non pitting oedema, calf circumference (difference over 3 cm suggests deep vein thrombosis), skin changes (peau d'orange, hyperkeratosis, ulcers), Stemmer sign (inability to pinch the dorsal skin fold of the second toe), pulses, capillary refill, pain on passive stretch, tense compartments.
• Neck: thyroid movement on swallowing, thyroglossal cyst movement on tongue protrusion, lymph node groups, parotid and submandibular glands.
• Breast: both breasts, axillae, nipple discharge.
• Groin and scrotum: hernia orifices, testis separate from lump, cord, transillumination, Prehn sign.
• Joints: effusion (patellar tap), warmth, range of movement.
• Face and airway: lip, tongue, uvula swelling, stridor, voice change, urticaria.
• Skin over the swelling and adjacent drainage.

Red flags.

• Airway swelling: tongue, lips, throat, stridor, drooling, voice change.
• Rapidly spreading erythema with severe pain out of proportion, bullae, crepitus, systemic toxicity (necrotising infection).
• Tense, painful limb with pain on passive stretch (compartment syndrome); pale, pulseless, cold limb (acute ischaemia).
• Acute scrotal pain with high riding testis (torsion).
• Irreducible, tender hernia with vomiting (strangulation).
• Unilateral limb swelling with pain (deep vein thrombosis) especially with chest symptoms.
• Lump over 5 cm, growing, deep, hard, fixed, painful, or recurrent after excision.
• Supraclavicular, hard, matted or fixed lymph nodes; generalised lymphadenopathy with weight loss, night sweats or splenomegaly.
• Breast lump with skin dimpling, nipple retraction, bloody discharge, axillary nodes.
• Thyroid nodule with hoarseness, fixed to surrounding structures, rapid growth, or family history of medullary thyroid carcinoma.
• Immunosuppression or diabetes with spreading infection.

Inflammatory and infective. Cellulitis, abscess, necrotising fasciitis, pyomyositis, septic arthritis, osteomyelitis, infected cyst. Infected lymph nodes (staphylococcal, streptococcal, cat scratch disease, tuberculosis, atypical mycobacteria, brucellosis, syphilis, lymphogranuloma venereum, HIV). Mumps and bacterial parotitis, dental abscess, Ludwig angina, hidradenitis suppurativa, mastitis, epididymo-orchitis. Filariasis, onchocerciasis, cutaneous leishmaniasis, hydatid cyst, mycetoma, cysticercosis, tungiasis.

Vascular and haematological. Deep vein thrombosis, superficial thrombophlebitis, arterial aneurysm, venous malformation, haemangioma, varicose veins, haematoma, bleeding disorder, anticoagulant haemorrhage, lymphoedema (primary, filarial, post surgical, post radiation, malignant), lymphatic malformation, venous insufficiency, vascular compartment syndrome.

Neoplastic.

• Benign: lipoma, fibroma, neurofibroma, schwannoma, adenoma, fibroadenoma, osteochondroma.
• Malignant: soft tissue sarcoma, lymphoma, metastatic node, breast cancer, thyroid cancer, salivary gland tumour, melanoma, squamous cell carcinoma, testicular tumour, bone sarcoma, Kaposi sarcoma, leukaemia infiltrates.

Cystic and developmental. Epidermoid and sebaceous cyst, ganglion, Baker cyst, branchial cyst, thyroglossal cyst, cystic hygroma, dermoid cyst, hydrocele, spermatocele, pilonidal sinus, Bartholin cyst.

Hernia and structural. Inguinal, femoral, umbilical, incisional, epigastric and spigelian hernias, abdominal wall defect, diastasis recti, lipoma of the cord.

Endocrine and systemic. Goitre and thyroid nodule, thyroid eye disease, myxoedema, acromegaly, hypoalbuminaemia (nephrotic syndrome, liver disease, malnutrition), heart failure, chronic kidney disease, venous insufficiency, drugs causing oedema (amlodipine, NSAIDs, corticosteroids, pioglitazone), Cushing syndrome.

Allergic and angioedema. Allergic angioedema and anaphylaxis, ACE inhibitor angioedema, hereditary angioedema, acquired C1 esterase inhibitor deficiency, contact dermatitis, insect bite reaction.

Musculoskeletal. Fracture, haematoma, myositis ossificans, bursitis, tenosynovitis, gout, pseudogout, osteoarthritis, rheumatoid arthritis, effusion, heterotopic ossification, Paget disease, bone tumour, osteomyelitis, compartment syndrome.

Others. Foreign body granuloma, sarcoidosis, IgG4 related disease, Castleman disease, subcutaneous nodules (rheumatoid, gouty tophi), lipodystrophy, injection site reactions.

1. Clinical triage into time critical (airway, necrotising infection, compartment syndrome, torsion, strangulated hernia, arterial occlusion), probably benign and indeterminate or suspicious for malignancy.
2. Basic tests: full blood count with film, ESR and C reactive protein, urea, creatinine, electrolytes, liver function tests, albumin, glucose, coagulation screen when bleeding is suspected, and urinalysis for protein.
3. Ultrasound is the first imaging for most lumps (cystic or solid, vascular flow with Doppler, lymph node architecture, hernia, muscle, joint effusion, thyroid, breast, scrotum, soft tissue). Doppler ultrasound for deep vein thrombosis (with D-dimer under 500 ng/mL excluding it when pretest probability is low).
4. MRI for soft tissue masses over 5 cm, deep lesions, suspected sarcoma, vascular malformation, and for assessment of extent. CT for chest, abdomen and pelvis staging, neck masses, abscess and bone. Plain radiographs for bone and calcification. Do not excise a deep or large mass before imaging and biopsy planning.
5. Tissue diagnosis: fine needle aspiration for nodes, thyroid and breast; core needle biopsy for soft tissue masses and nodes (preferred for suspected lymphoma and sarcoma); excision biopsy for suspected lymphoma node; incision biopsy planned with the surgical team in suspected sarcoma. Triple assessment (clinical, imaging, needle biopsy) for breast lumps.
6. Infection: culture of aspirate or pus, blood cultures, HIV test with consent, Mantoux or interferon gamma release assay, acid fast stain and GeneXpert on aspirate, Bartonella, brucella and syphilis serology, filarial antigen test or night blood film in endemic areas, hydatid serology, leishmania microscopy.
7. Endocrine and thyroid: thyroid stimulating hormone, thyroid ultrasound, fine needle aspiration of nodules over 1 cm with suspicious features, calcitonin if medullary carcinoma is suspected.
8. Angioedema: complement C4 (low in hereditary angioedema), C1 esterase inhibitor level and function, tryptase within 3 hours of anaphylaxis.
9. Hernia: clinical diagnosis; ultrasound when uncertain. Scrotum: urgent Doppler ultrasound if torsion is not clinical certain, but do not delay surgery.
10. Staging imaging and multidisciplinary review when malignancy is confirmed.

Limits. Fine needle aspiration cannot reliably grade lymphoma or sarcoma. Ultrasound is operator dependent. Normal D-dimer excludes deep vein thrombosis only at low probability. Tissue sampling errors occur in heterogeneous masses.

Emergencies.

• Airway angioedema or anaphylaxis: adrenaline 0.5 mg (0.5 mL of 1 in 1,000) intramuscularly into the anterolateral thigh, repeated every 5 minutes as needed; oxygen; chlorphenamine 10 mg intravenously; hydrocortisone 200 mg intravenously; intravenous crystalloid 500 to 1000 mL; airway management.
• For hereditary angioedema: icatibant 30 mg subcutaneously (may repeat after 6 hours, maximum 3 doses in 24 hours), or C1 esterase inhibitor 20 units/kg intravenously. Adrenaline, antihistamines and steroids do not work.
• ACE inhibitor angioedema: stop the drug permanently, airway observation, and switch to a different class.
• Necrotising soft tissue infection: urgent surgical debridement, broad spectrum antibiotics (piperacillin-tazobactam 4.5 g intravenously every 6 hours with clindamycin 600 to 900 mg intravenously every 8 hours, add vancomycin 15 to 20 mg/kg every 8 to 12 hours when MRSA is a risk), intensive care.
• Compartment syndrome: remove constrictive dressings, keep the limb at heart level, and urgent fasciotomy.
• Acute limb ischaemia: heparin 5,000 units intravenously and urgent vascular surgery.
• Testicular torsion: immediate surgical exploration (best within 6 hours).
• Strangulated hernia: nil by mouth, fluids, analgesia, surgery.
• Deep vein thrombosis: rivaroxaban 15 mg twice daily for 21 days then 20 mg daily (or apixaban 10 mg twice daily for 7 days then 5 mg twice daily), for at least 3 months; avoid in severe renal impairment and active bleeding; compression for symptoms.

Cause directed treatment.

• Abscess: incision and drainage, culture, and antibiotics when cellulitis, immunosuppression or systemic illness. Flucloxacillin 500 mg to 1 g orally every 6 hours for 5 to 7 days (clindamycin 300 to 450 mg every 6 to 8 hours or doxycycline 100 mg twice daily if penicillin allergic or MRSA).
• Cellulitis: flucloxacillin 500 mg to 1 g orally every 6 hours for 5 to 7 days, or intravenous 1 to 2 g every 6 hours if severe; elevate the limb; review at 48 hours.
• Infective lymphadenitis: treat the source; needle aspiration rather than incision of tuberculous nodes.
• Tuberculous nodes: four drug regimen (isoniazid 5 mg/kg, rifampicin 10 mg/kg, pyrazinamide 25 mg/kg, ethambutol 15 mg/kg for 2 months then isoniazid and rifampicin for 4 months, extended to 9 to 12 months for some forms), plus pyridoxine.
• Lymphoedema: compression garments, skin care, manual lymphatic drainage, exercise, and treatment of cellulitis. Filariasis: albendazole 400 mg orally with diethylcarbamazine 6 mg/kg once yearly, hygiene, and doxycycline 200 mg daily for 6 weeks for lymphoedema stabilisation where available.
• Hernia: elective repair for symptomatic hernias; urgent for femoral hernias.
• Benign cysts and lipomas: reassurance; surgical excision for symptoms, infection or diagnostic uncertainty.
• Suspected malignancy: refer for urgent assessment (within 2 weeks in most systems), do not excise before imaging and biopsy for deep or large masses.
• Haematoma: rest, ice, compression, and review anticoagulation; drain if tense or infected.
• Gout and septic arthritis: aspirate joints. Give urgent antibiotics (flucloxacillin 2 g intravenously every 6 hours) for septic arthritis. For gout use colchicine 500 micrograms two to three times daily, or naproxen 750 mg then 250 mg every 8 hours, or prednisolone 30 to 35 mg daily for 5 days.
• Thyroid nodules: thyroid function and ultrasound directed management, surgery for malignancy or compressive symptoms.
• Oedema from heart, liver or kidney disease: treat the disease; furosemide 40 mg orally once daily (titrate), spironolactone 100 mg for ascites, salt restriction, and leg elevation. Drug induced oedema: reduce the dose or change the drug.

Analgesia. Paracetamol 1 g every 6 hours (maximum 4 g; 3 g if frail or under 50 kg), ibuprofen 400 mg every 8 hours with food (maximum 2.4 g) when no contraindication.

Monitoring. Re-examine at 1 to 2 weeks for non urgent swellings; re-measure size. Any swelling growing, persisting beyond 4 to 6 weeks, or recurring requires imaging and tissue diagnosis. Review wound and culture results.

Referral and escalation. Urgent surgical, vascular or ENT referral for time critical causes. Two week referral to a rapid diagnostic service or sarcoma, haematology or breast unit for suspicious lumps. Dermatology for skin lesions. Infectious diseases for tuberculosis, filariasis and unusual infections. Immunology for recurrent angioedema.

Admission. Airway compromise, sepsis, necrotising infection, compartment syndrome, arterial or venous occlusion with instability, strangulated hernia, torsion, large or rapidly spreading cellulitis, septic joint, or need for intravenous antibiotics.

Safety netting. Return for growth, pain, fever, redness, discharge, difficulty swallowing or breathing, numbness, a cold or pale limb, or persistence beyond the expected time.

Special groups. Children: reactive nodes are common; persistent or large nodes, supraclavicular nodes, and nodes with systemic symptoms need review; consider congenital cysts, haemangiomas and lymphatic malformations. Pregnancy: avoid radiation where possible; use ultrasound and MRI; deep vein thrombosis is treated with enoxaparin 1 mg/kg twice daily. Older adults: malignancy is more likely; lower threshold for imaging and biopsy.

Immunosuppressed and HIV: tuberculosis, lymphoma, Kaposi sarcoma and opportunistic infection. Endemic regions: filariasis, mycetoma, hydatid disease, tungiasis and tuberculosis are frequent.