Poison-oak-like symptoms on his lower back and legs, they're swollen; poison-oak-like symptoms on his lower back and legs, they're ulceration; feels a little funny; Little confuse for a day or two; poison-oak-like symptoms on his lower back and legs, they're rash; This spontaneous case was reported by a patient and describes the occurrence of SKIN SWELLING (Poison-oak-like symptoms on his lower back and legs, they're swollen), SKIN ULCER (poison-oak-like symptoms on his lower back and legs, they're ulceration), FEELING ABNORMAL (feels a little funny), CONFUSIONAL STATE (Little confuse for a day or two) and RASH (poison-oak-like symptoms on his lower back and legs, they're rash) in a 55-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for Prophylactic vaccination.    Co-suspect product included non-company product DUPILUMAB (DUPIXENT) injection, solution for Dermatitis atopic, Skin swelling, Skin ulcer and Rash.    Patient's past medical history, medical treatment(s) and family history were not provided.    On 21-Feb-2022, the patient DUPILUMAB (DUPIXENT) (Subcutaneous) dosage was changed to 600 milligram once a day. On an unknown date, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form and DUPILUMAB (DUPIXENT) (unknown route) 300 milligram. On an unknown date, the patient experienced SKIN SWELLING (Poison-oak-like symptoms on his lower back and legs, they're swollen), SKIN ULCER (poison-oak-like symptoms on his lower back and legs, they're ulceration), FEELING ABNORMAL (feels a little funny), CONFUSIONAL STATE (Little confuse for a day or two) and RASH (poison-oak-like symptoms on his lower back and legs, they're rash). At the time of the report, SKIN SWELLING (Poison-oak-like symptoms on his lower back and legs, they're swollen), SKIN ULCER (poison-oak-like symptoms on his lower back and legs, they're ulceration) and RASH (poison-oak-like symptoms on his lower back and legs, they're rash) had not resolved and FEELING ABNORMAL (feels a little funny) and CONFUSIONAL STATE (Little confuse for a day or two) outcome was unknown.        The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.       Concomitant medication was not provided.  The patient took Dupixent (dupilumab) pre-filled pen, 600 mg loading dose subcutaneously (SQ) taken on 21-Feb-2022, followed by a 300 mg maintenance dose subcutaneously every other week. First time product used: no. The patient took dupilumab for poison-oak-like symptoms on lower back and legs - they're swollen, rash or ulceration which was categorized as product use in unapproved indication.  The patient had an adverse event previously reported: having to do with taking the Moderna vaccine and having a severe reaction and being prescribed Dupixent to deal with that reaction. And part of the reaction involved poison-oak-like symptoms on lower back and legs - they're swollen, and rash or ulceration. The poison-oak-like symptoms resolved on Dupixent but recently they have come back. It was also reported that after each Dupixent injection, felt a little funny, a little confused for a day or two. At the time of the report, Dupixent was continued. The patient was prescribed dupilumab for skin swelling, skin ulcer and rash. It was not reported if the patient received a corrective treatment for the events confused, felt a little funny.