Herpes Simplex

Overview – Herpes Simplex

Herpes simplex is a common, often recurrent viral infection caused by the herpes simplex virus (HSV), with distinct Type 1 and Type 2 strains. HSV-1 typically affects the oral and facial region, while HSV-2 is more often associated with genital infections. The virus resides latently in nerve ganglia and can reactivate intermittently, often triggered by stress, illness, or UV exposure. Clinically, herpes simplex presents with painful vesicles, localised blistering, and neuralgia. Management includes supportive care and antiviral therapy, particularly for severe or recurrent cases.

Definition

Herpes simplex is a mucocutaneous viral infection caused by the herpes simplex virus (HSV), characterised by vesicular eruptions that progress through distinct clinical stages. The virus has a lifelong presence in the body due to its ability to remain dormant in nerve ganglia and reactivate under various triggers.

Aetiology

• Caused by herpes simplex virus (HSV), a DNA virus from the Herpesviridae family
• Two types:
  • HSV-1: Primarily causes oral/facial lesions (e.g. cold sores)
  • HSV-2: Primarily causes genital herpes

Pathophysiology

• Primary infection often occurs via direct mucosal or skin contact
• Virus travels via sensory nerves to regional ganglia (e.g. trigeminal or sacral)
• Reactivation leads to viral replication and travel back to skin/mucosa
• Resulting in blistering and associated symptoms (pain, burning, itching)
• Viral latency allows recurrent episodes

Clinical Features

Stages of Infection:

1. Prodromal stage – burning, tingling, or pain in affected area
2. Vesicle stage – grouped, fluid-filled blisters on erythematous base
3. Ulcer stage – vesicles rupture, forming shallow painful ulcers
4. Crust stage – ulcers dry, crust, and heal

Other Features:

• Localised blistering, commonly on lips (HSV-1) or genitals (HSV-2)
• Neuralgia (burning or shooting nerve pain)
• Lymphadenopathy (enlarged lymph nodes)
• High fever in primary infections, especially in children

Recurrence Triggers

• Emotional stress
• UV radiation (sun exposure)
• Menstruation or hormonal changes
• Trauma or procedures (e.g. dental work)
• Other infections or immune suppression

Management

• Mild cases: often self-limiting, no treatment required
• General measures:
  • Sun protection (especially to prevent HSV-1 outbreaks)
  • Avoid direct skin-to-skin contact during active outbreaks
• Antiviral therapy:
  • Oral aciclovir, valaciclovir, or famciclovir
  • Reduces symptom duration and viral shedding
  • Especially useful for severe, recurrent, or immunocompromised patients

Complications

• Herpes encephalitis – life-threatening CNS infection; emergency
• Trigeminal neuralgia – chronic neurogenic pain, post-HSV-1 facial involvement
• Herpetic whitlow – HSV infection of the fingers, often in healthcare workers
• Erythema multiforme – can follow HSV infection in some cases

Differential Diagnosis

• Aphthous ulcers
• Impetigo (especially in children)
• Contact dermatitis
• Syphilis (genital lesions)
• Hand-foot-and-mouth disease (in children)

Summary – Herpes Simplex

Herpes simplex is a lifelong viral infection that presents with recurrent vesicular eruptions, most commonly in oral or genital regions. Caused by HSV-1 or HSV-2, the infection progresses through classic blister–ulcer–crust stages and may be accompanied by neuralgia or fever. Treatment includes supportive care and antivirals in moderate to severe cases. For a broader dermatological context, visit our Skin & Dermatology Overview page.