Postherpetic neuralgia is a nerve pain.
The neuralgia typically begins when the herpes zoster vesicles have crusted over and begun to heal, but can begin in the absence of herpes zoster—a condition called zoster sine herpete (see Herpes zoster).
Patients with postherpetic neuralgia (PHN) always suffer persistent and severe breakthrough pain (BTP) which may arise from nerve changes virus affection or immune response. BTP is characterized by brief duration (median 30 min), a severe intensity, rapid onset (less than 3 minutes), and daily frequency (more than 4 episodes per day) 2).
Typically, the neuralgia is confined to a dermatomic area of the skin, and follows an outbreak of herpes zoster (commonly known as shingles) in that same dermatomic area.