Question:medium
A 56 year old man has painful rashes over his right upper eyelid and forehead for the last 48 hours. He underwent chemotherapy for Non-Hodgkin's lymphoma one year ago. His temperature is 98 degree F, blood pressure 138/76 mm Hg, and pulse is 80/minute. Examination shows no other abnormalities. Which of the following is the most likely diagnosis?
A 56 year old man has painful rashes over his right upper eyelid and forehead for the last 48 hours. He underwent chemotherapy for Non-Hodgkin's lymphoma one year ago. His temperature is 98 degree F, blood pressure 138/76 mm Hg, and pulse is 80/minute. Examination shows no other abnormalities. Which of the following is the most likely diagnosis?
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Painful rash along the V1 dermatome in an immunocompromised patient points to shingles.
Updated On: Jul 8, 2026
- Impetigo
- Herpes zoster
- Pyoderma gangrenosum
- Erysipelas
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The Correct Option is B
Solution and Explanation
Step 1: Start with the immune status.
A history of chemotherapy for lymphoma a year ago tells us this man's cell-mediated immunity is likely still weak. That single fact should make us think of reactivation infections.
Step 2: Match the rash to a nerve, not just a body part.
The right upper eyelid and forehead are covered by one nerve branch, the ophthalmic branch of the trigeminal nerve (V1). Painful skin disease that sits exactly along one nerve's territory, and stays on one side of the midline, is a strong clue.
Step 3: Recall which virus hides in nerve ganglia.
Varicella-zoster virus, the chickenpox virus, sits quietly in a dorsal root or cranial nerve ganglion for years after the first infection. When immunity drops, as it does after chemotherapy, the virus wakes up and spreads along that one nerve, causing herpes zoster.
Step 4: Check the pain and fever pattern.
Herpes zoster often causes pain before the rash even shows up, and this patient has severe pain with a rash only two days old, but a normal temperature and pulse, unlike a spreading bacterial skin infection which usually brings fever and systemic illness.
Step 5: Cross off the bacterial mimics.
Impetigo is superficial and crusted, not dermatomal or this painful. Erysipelas is a spreading, feverish bacterial infection. Pyoderma gangrenosum makes deep ulcers, usually on the legs, tied to bowel or blood disease, and does not follow a nerve.
Step 6: Conclude.
The nerve-bound painful rash in this immunocompromised man is herpes zoster.
\[ \boxed{\text{Herpes zoster}} \]
A history of chemotherapy for lymphoma a year ago tells us this man's cell-mediated immunity is likely still weak. That single fact should make us think of reactivation infections.
Step 2: Match the rash to a nerve, not just a body part.
The right upper eyelid and forehead are covered by one nerve branch, the ophthalmic branch of the trigeminal nerve (V1). Painful skin disease that sits exactly along one nerve's territory, and stays on one side of the midline, is a strong clue.
Step 3: Recall which virus hides in nerve ganglia.
Varicella-zoster virus, the chickenpox virus, sits quietly in a dorsal root or cranial nerve ganglion for years after the first infection. When immunity drops, as it does after chemotherapy, the virus wakes up and spreads along that one nerve, causing herpes zoster.
Step 4: Check the pain and fever pattern.
Herpes zoster often causes pain before the rash even shows up, and this patient has severe pain with a rash only two days old, but a normal temperature and pulse, unlike a spreading bacterial skin infection which usually brings fever and systemic illness.
Step 5: Cross off the bacterial mimics.
Impetigo is superficial and crusted, not dermatomal or this painful. Erysipelas is a spreading, feverish bacterial infection. Pyoderma gangrenosum makes deep ulcers, usually on the legs, tied to bowel or blood disease, and does not follow a nerve.
Step 6: Conclude.
The nerve-bound painful rash in this immunocompromised man is herpes zoster.
\[ \boxed{\text{Herpes zoster}} \]
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