What condition is characterized by severe pain in the dermatomes after a herpes zoster infection?

Postherpetic neuralgia is a condition that occurs as a complication of herpes zoster, commonly known as shingles. After the initial outbreak of herpes zoster, which is caused by the reactivation of the varicella-zoster virus (the virus that causes chickenpox), some individuals may experience persistent nerve pain in the areas of the skin that correspond to the affected dermatomes. This pain can be severe and may last for months or even years after the initial rash has healed.

The pain associated with postherpetic neuralgia can be described as burning, stabbing, or aching and may be aggravated by light touch or temperature changes. It results from nerve damage caused by the viral infection, leading to abnormal pain processing in the nervous system. This distinguishes it from other conditions that do not primarily involve nerve pain resulting from herpes zoster infection.

The other options listed, such as chronic gastritis, pernicious anemia, and acute pancreatitis, are unrelated to the effects of herpes zoster and do not involve the hallmark symptom of severe pain in the dermatomes linked to a prior viral infection. Thus, postherpetic neuralgia is the clear answer, reflecting the appropriate association between shingles and the characteristic pain that follows.