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InfectiousICD-10: B00HSV-1 affects about 3.7 billion people globally (67% under 50)

Herpes Simplex

Also known as: HSV, Cold Sores, Fever Blisters, Oral Herpes

Herpes simplex virus infections are caused by HSV-1 (primarily oral herpes) and HSV-2 (primarily genital herpes). HSV-1 is extremely common, with most people acquiring it during childhood. The virus remains dormant in nerve cells and can reactivate periodically, causing recurrent outbreaks that become less frequent over time.

Symptoms

Tingling, itching, or burning before sores appear (prodrome)
Painful fluid-filled blisters on or around the lips, mouth, or genitals
Sores that break open, weep, and crust over
Fever and malaise during the first outbreak
Swollen lymph nodes near the affected area
Pain during urination if sores are near the urethra

Causes

  • HSV-1 transmitted through oral contact
  • HSV-2 transmitted through sexual contact
  • Direct skin-to-skin contact with an infected person
  • Asymptomatic viral shedding between outbreaks

Risk Factors

  • Close contact with someone who has HSV
  • Multiple sexual partners (HSV-2)
  • Weakened immune system
  • Stress, illness, or fatigue triggering reactivation

Diagnosis

  • Viral culture or PCR test from an active sore
  • Type-specific blood tests for HSV-1 and HSV-2 antibodies
  • Clinical examination of characteristic lesions

Treatment

  • Antiviral medications (acyclovir, valacyclovir, famciclovir)
  • Topical antiviral creams for mild oral outbreaks
  • Daily suppressive therapy for frequent recurrences
  • Pain relief with over-the-counter analgesics
  • Keeping sores clean and dry

Prevention

  • Avoid kissing or sharing utensils during active cold sore outbreaks
  • Use condoms to reduce genital HSV transmission
  • Avoid touching sores and wash hands after contact
  • Daily antiviral therapy to reduce transmission

When to See a Doctor

  • You are unsure if sores are caused by herpes
  • Outbreaks are frequent (more than 6 per year) or severe
  • You have a weakened immune system and develop sores
  • Sores appear near the eyes, which can threaten vision

Frequently Asked Questions

Related Conditions

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Medical Disclaimer: This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.

Content reviewed against peer-reviewed medical literature and clinical guidelines. Read our editorial standards.