Multimodality imaging approach to complex regional pain syndrome of the hand following herpes zoster

Abstract A 75-year-old man with well-controlled diabetes mellitus (type 2) developed a typical zoster rash over his right scapular region. Therapy included systemic valacyclovir and topic acyclovir. During follow-up a second painful herpetic rash appeared over his right hand. Therapy was integrated with codeine/acetaminophen. Both rash and pain improved but did not disappear. Three weeks later the patient complained of a strong pain and edema in his right hand. Pain was described as constant and deep, burning on the third finger. The right hand and the fingers were swollen; skin was warm, taut and glossy. Strength was reduced in the territory of the ulnar nerve. Serum analysis were normal. Ultrasonography (US) and magnetic resonance imaging (MRI) of both hands were requested. US showed diffuse thickening of the subcutaneous layers. MR demonstrated a small amount of fluid in the metacarpophalangeal joint of the thumb, diffuse soft tissue swelling, and intramuscular edema, more evident at the thenar eminence. Findings suggested complex regional pain syndrome (CRPS). The diagnosis was confirmed by patient's follow-up. To the best of our knowledge this is the first time that both MRI and US were performed in a case of CRPS of the hand following herpes zoster. Since CRPS is possible in subjects with herpes zoster affecting the distal extremity and indicates increased risk for development of post-herpetic neuralgia (PHN) a correct diagnosis is mandatory to prevent such complication. Combined MRI and US examination may help clinicians making an early diagnosis especially when the syndrome appears as a relatively limited syndrome in which naturopathic pain/sensory abnormalities predominate.