How do I differentiate between parotitis and lymphadenitis, including history taking, examination, and treatment?

Differentiating Parotitis from Lymphadenitis

The key distinction is anatomical location: parotitis involves swelling within the parotid gland itself (diffuse, overlying the angle of the mandible, obscuring the earlobe), while lymphadenitis presents as discrete, mobile nodules that are separate from the parotid gland and typically located along the anterior or posterior cervical chain. 1

History Taking

Parotitis-Specific Features

• Recurrent episodes of painful swelling in the same location, often with a history spanning months to years 2, 3
• Meal-related pain (increased salivation triggers pain if ducts are obstructed) 3
• Bilateral involvement in 5-10% of cases, though usually asymmetric 4
• Systemic viral symptoms (mumps, EBV, CMV) if acute viral parotitis 1
• Dry mouth symptoms or decreased salivation between episodes 3

Lymphadenitis-Specific Features

• Recent upper respiratory infection (reported in 22-53% of cases) 5
• Unilateral presentation in 95% of cases 1, 6
• Exposure history: TB contact, animal exposures, travel history 7
• Age matters: In children, nontuberculous mycobacteria (NTM) are most common (ages 1-5 years); in adults >90% of mycobacterial lymphadenitis is tuberculous 1, 6
• Systemic symptoms: fever, night sweats, weight loss suggest TB or lymphoma 1, 7

Physical Examination

Parotitis Examination

• Location: Swelling is diffuse, overlying the angle of the mandible, extending from the zygomatic arch to below the angle of the jaw, obscuring the earlobe 1
• Texture: Firm, diffuse enlargement of the entire gland (not a discrete nodule) 3
• Stensen's duct: Examine the buccal mucosa opposite the upper second molar—look for purulent discharge, erythema, or stone at the duct opening 3
• Bimanual palpation: Place one finger intraorally and one externally to assess the gland substance itself 1
• Facial nerve function: Test all branches—weakness suggests malignancy, not simple parotitis 1

Lymphadenitis Examination

• Location: Discrete, mobile nodules along the anterior cervical chain (jugulodigastric region most common), posterior cervical chain, or submandibular region—separate from and anterior/posterior to the parotid gland 1
• Size: Nodes >1.5 cm are suspicious for malignancy 1
• Mobility: Reduced mobility, firm texture, or matted/fused nodes suggest malignancy or granulomatous disease (TB, NTM) 1, 7
• Tenderness: Nontender nodes are more suspicious for malignancy than tender nodes 1
• Skin changes: Look for overlying erythema, warmth (bacterial), or violaceous discoloration with potential fistula formation (mycobacterial) 1, 6
• Complete head/neck exam: Examine scalp, oral cavity (remove dentures), oropharynx (tonsil asymmetry), and palpate thyroid 1

Critical Differentiating Maneuver

Palpate the angle of the mandible: If you can clearly feel the bony angle through the swelling, it's likely lymphadenitis (nodes are anterior or posterior to the gland). If the angle is obscured by diffuse swelling, it's parotitis 1.

Diagnostic Workup

For Suspected Parotitis

• Ultrasound is first-line: differentiates intraparotid vs. extraparotid masses, identifies stones, assesses duct dilation 1
• CT with contrast if acute bacterial parotitis is suspected (abscess formation) 1
• MRI with and without contrast if chronic/recurrent parotitis or concern for deep lobe involvement or malignancy 1
• Sialography (CT or MRI) if duct obstruction suspected 1

For Suspected Lymphadenitis

• Tuberculin skin test (PPD) in all patients with suspected mycobacterial lymphadenitis 1, 6
• Chest X-ray to exclude pulmonary TB 6
• Fine-needle aspiration (FNA) for cytology and culture (mycobacterial, bacterial) 1, 6
• Complete blood count, ESR, CRP if systemic symptoms present 7
• CT neck with contrast shows ring-enhancing masses with minimal fat stranding in NTM lymphadenitis 1
• Excisional biopsy if FNA nondiagnostic or if nodes persist >4 weeks despite appropriate antibiotics 1, 7

Caution: Avoid incision and drainage or incomplete excision of suspected mycobacterial lymphadenitis—this leads to chronic fistula formation 1, 6.

Treatment

Parotitis Treatment

• Acute bacterial parotitis: Empiric antibiotics covering Staphylococcus aureus (including MRSA if risk factors present) plus oral anaerobes—amoxicillin-clavulanate or clindamycin 3
• Supportive care: Hydration, sialagogues (lemon drops, massage), warm compresses 3
• Chronic recurrent parotitis: Conservative management with hydration and anti-inflammatories; consider glucocorticoids in severe cases 2
• Surgical parotidectomy reserved for stage III chronic parotitis with complete lymphatic transformation (no spontaneous healing expected) 2

Lymphadenitis Treatment

• Bacterial lymphadenitis: Empiric antibiotics covering Staphylococcus aureus and Group A Streptococcus—amoxicillin-clavulanate or cephalexin 1
• NTM lymphadenitis in children: Complete surgical excision without chemotherapy (95% cure rate) 1, 6
• Tuberculous lymphadenitis: Standard 4-drug TB therapy (isoniazid, rifampin, pyrazinamide, ethambutol) for 6-9 months 1, 6
• Avoid incisional biopsy alone or anti-TB drugs without macrolides for NTM—both lead to fistula formation 6

Key Pitfall

Do not start corticosteroids empirically—they mask the histologic diagnosis of lymphoma or other malignancy 7. If lymphadenopathy persists >4 weeks or nodes are >2 cm, hard, or matted, obtain tissue diagnosis before any immunosuppressive therapy 1, 7.

budget:budget_used Token usage: approximately 18,500 tokens (well within 200,000 limit)