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Differentiating Mumps, Measles, Rubella, and Herpes

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Quick Overview Table

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1. Measles (Rubeola)

• Classic triad (3 Cs): Cough, Coryza (runny nose), Conjunctivitis
• Fever: High-grade (up to 40°C), appears first
• Pathognomonic sign: Koplik's spots — bluish-white spots on a red base on the buccal mucosa, appearing 1–2 days before the rash
• Rash: Maculopapular, starts on face/hairline, spreads head-to-toe (cephalocaudal) over 3–4 days; lesions may coalesce; lasts ~5–6 days
• Lymphadenopathy: Generalized, non-tender
• Lab: Leukopenia is characteristic
• Complications: Pneumonia, encephalitis, subacute sclerosing panencephalitis (SSPE)

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2. Mumps

• No skin rash — this is the key distinguishing feature
• Hallmark: Parotid gland swelling (parotitis) — unilateral or bilateral, tender, doughy swelling; raises the earlobe
• Fever: Moderate
• Other gland involvement: Submandibular, sublingual salivary glands
• Complications:
  • Orchitis (in post-pubertal males) — leading cause of viral orchitis
  • Oophoritis, pancreatitis, aseptic meningitis, sensorineural deafness
• Lab: Elevated serum amylase/lipase; lymphocytosis

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3. Rubella (German Measles)

• Milder than measles — often called "3-day measles"
• Prodrome: Low-grade fever, malaise — much less severe than measles; no cough
• Pathognomonic sign: Forchheimer spots — petechiae on the soft palate (less reliable than Koplik's)
• Rash: Fine, pink maculopapular, starts on face, spreads caudally in 24–48 hours; lesions remain discrete (do not coalesce); resolves in ~3 days
• Lymphadenopathy: Postauricular, occipital, and posterior cervical — tender, appears before the rash — classic distinguishing feature from measles
• No conjunctivitis or cough (key difference from measles)
• Most dangerous in pregnancy: Congenital Rubella Syndrome (cataracts, cardiac defects, deafness)

Rubella: discrete, blanching pink maculopapular rash spreading caudally, with postauricular lymphadenopathy (DermNetNZ)

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4. Herpes (HSV & VZV)

Herpes Simplex Virus (HSV-1 / HSV-2)

• HSV-1: Orolabial herpes — "cold sores" on lips/perioral; clustered vesicles on erythematous base
• HSV-2: Genital herpes — vesicles/ulcers on genitalia; painful
• Prodrome: Tingling/burning/itching before vesicle formation
• Lesion pattern: Grouped vesicles → rupture → painful ulcers → crust
• Recurrent: Virus remains latent in dorsal root/trigeminal ganglia

Herpes Zoster (VZV Reactivation / "Shingles")

• Dermatomal distribution — unilateral, does not cross midline
• Prodrome: Severe dermatomal pain/burning before rash appears (can mimic MI, pleuritis, etc.)
• Rash: Vesicles on erythematous base in a belt-like (zoster = belt) distribution
• Common dermatomes: T3–L3; also ophthalmic branch of trigeminal (Herpes Zoster Ophthalmicus)
• Complications: Postherpetic neuralgia, Ramsay Hunt syndrome (CN VII), encephalitis
• Diagnosis: Clinical; PCR of vesicular fluid for confirmation in atypical cases

Varicella (Primary VZV / Chickenpox)

• Rash: Pleomorphic — lesions in different stages simultaneously (macules, papules, vesicles, pustules, crusts)
• Distribution: Centripetal (starts on trunk, spreads to face and extremities)
• Intensely pruritic
• Prodrome: 1–2 days of fever before rash

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Key Differentiating Summary

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Diagnosis Confirmation