Hi, welcome to the forum, Nonsteroidal antiinflammatory drugs (NSAIDs), including aspirin, diclofenac and ibuprofen, are associated with an allergic adverse effects, ranging from mild rash to life-threatening allergic reactions. In such cases it becomes difficult to select appropriate pain killer. The next we usually recommend is paracetamol (she is also allergic to this drug). The reason for such allergy is cross reactivity which is seen in this class of drugs.
The group of painkillers which do not cross react with above mentioned painkillers are selective COX inhibitors like Rofecoxib, Valdecoxib or etoricoxib. Etoricoxib is quite safe can be given in her case, but against prescription. But I would suggest you to consult physician and discuss about appropriate painkillers. Take care and regards.
Thanks doc for the info, it is really helpful.