Cutaneous reaction to furosemide
Question:
12/20/2021
A 78-year-old female with a history of delayed drug rash to Lasix. The patient was started on Lasix for peripheral edema on 5/15. On 5/26 she began to have a slightly pruritic rash on right forearm that rapidly progressed to trunk and extremities. Took PO Benadryl at home with no resolution and then presented to the ED. She denied pain, fevers/chills, oral involvement and change to LFTs (although chronically elevated). She was admitted to the hospital and treated with Sarna and TAC to trunk for pruritus. She notes a history of many drug allergies and allergy to yellow dye. She notes she can tolerate yellow dye number 5 or 6 but not if it ends in the component "lake." Prior to this she used to be on HCTZ for many years with no issues. At this time, she is referred to me because her PCP would like to trial HCTZ again as ethacrynic acid has not been as efficacious. Would you patch test to Lasix and HCTZ and then consider trial if HCTZ is negative?
Answer:
You report that your patient had taken HCTZ in the past without adverse reaction. I do not feel atopy patch test or skin testing is necessary, rather initiate a trial of HCTZ.
I reached out to Dr. Eric Macy, an expert in drug allergy for additional thoughts. His comment as follows.
The reference standard test to determine current tolerance to furosemide in this setting would be to give a single therapeutic dose of furosemide and observe the patient for a delayed-onset rash over the next 5 to 7 days similar to the index event. Furosemide has been associated with photodermatitis. If another rash occurs, check liver function tests, an absolute eosinophil count, and get a skin biopsy if the lab tests are elevated.
I hope you find this helpful.
Respectfully submitted,
Jeffrey G. Demain, MD, FAAAAI