What is the typical distribution of shingles?

From the Guidelines

Shingles typically appears as a painful rash that develops on one side of the body, following a specific dermatome, most commonly on the torso, forming a band or belt-like pattern that wraps around one side of the chest or abdomen. The rash begins as red patches that develop into fluid-filled blisters, which eventually crust over. This distribution is unilateral (one-sided) in about 95% of cases, which is a key diagnostic feature distinguishing it from other skin conditions 1. The one-sided pattern occurs because the varicella-zoster virus, which causes shingles, reactivates within a specific nerve ganglion and travels along that nerve pathway to the skin.

Key Characteristics of Shingles Distribution

• The rash is typically unilateral, affecting one side of the body
• The most common distribution is on the torso, forming a band or belt-like pattern
• Shingles can also affect the face, neck, limbs, or any other part of the body
• The rash begins as red patches that develop into fluid-filled blisters, which eventually crust over

According to the most recent and highest quality study, the typical distribution of shingles is characterized by a unilateral, vesicular eruption with dermatomal pain that often precedes the skin findings by 24–72 hours 1. Early lesions are erythematous macules that rapidly evolve to papules and then to vesicles. The vesicles frequently coalesce, form bullae, and scab before healing.

Factors Influencing Shingles Distribution

• The virus remains dormant in nerve tissues after a person recovers from chickenpox, sometimes reactivating decades later to cause shingles
• The risk of shingles increases with age, particularly after 50 years of age
• Immunocompromised patients are at a higher risk of developing shingles and may experience more severe symptoms 1

From the Research

Typical Distribution of Shingles

The typical distribution of shingles is characterized by a unilateral and dermatomal pattern, meaning it affects one side of the body and follows a specific nerve pathway.

• The most common sites affected are:
  • Thoracic dermatomes (approximately 56%) 2
  • Cranial nerves (approximately 13%) 2
  • Lumbar (approximately 13%) 2
  • Cervical (approximately 11%) 2
  • Sacral nerves (approximately 4%) 2
• Among cranial nerves, the trigeminal and facial nerves are the most affected due to reactivation of HZV latent in gasserian and geniculated ganglia 2
• The 1st division of the trigeminal nerve is commonly affected, whereas the 2nd and the 3rd are rarely involved 2

Dermatomal Distribution

The dermatomal distribution of shingles is a key characteristic of the disease.

• Herpes zoster may affect any sensory ganglia and its cutaneous nerve, resulting in a painful cutaneous or mucocutaneous vesicular eruption that is generally limited to the single affected dermatome 2
• The rash typically appears in a band-like pattern, following the distribution of the affected nerve 3

Clinical Presentation

The clinical presentation of shingles can vary, but it is often characterized by:

• A vesicular rash with a unilateral and dermatomal distribution 3
• Pain, which can be severe and debilitating 4, 5, 6
• Prodromal symptoms, such as odontalgia, which can be a diagnostic challenge 2