P040 A Tale of Three Rashes

Abstract

Abstract Background/Aims Skin rashes are commonly an external marker of internal disease and are often useful in the diagnosis of a variety of systemic diseases managed by rheumatologists. I present a case of a lady who developed three discrete episodes of different skin rashes over the course of two months that represented three different underlying pathologies but were nevertheless intrinsically linked. Methods In September 2019, a 42-year-old lady returned from holiday in Thailand with mosquito bites on her arms and legs. She presented to another hospital with fevers, myalgias and severe arthralgias. Her CRP was raised at 128mg/l and she was given intravenous cefuroxime for 3 days followed by oral co-amoxiclav for presumed infected mosquito bites. Shortly after starting the intravenous cefuroxime, she developed a second rash on her torso, arms and legs. She was seen a week after discharge from hospital with ongoing severe arthralgias although her CRP had settled and was prescribed celecoxib 200mg twice daily. In October 2019, she developed pedal oedema and a non-blanching, purpuric rash across her shins bilaterally and presented to out-patient clinic. Results In clinic, she complained of widespread large and small joint polyarthralgias but there was no synovitis on examination. An anti-streptolysin O titer (ASOT) was negative but IgM and IgG antibodies to Chikungunya were positive. Her CRP was raised at 22 mg/l and a urinalysis was negative for blood and protein. A diagnosis of Chikungunya fever transmitted by mosquito bites was made followed by a maculopapular drug eruption secondary to cefuroxime and subsequent Henoch Schonlein Purpura (HSP) secondary to recent infection. Her symptoms were treated with a reducing course of prednisolone 40mg once a day and her rashes and arthralgias settled over the course of 2 months. Her urinalysis remained negative for blood and protein throughout. Conclusion Chikungunya virus is an arthropod-borne virus that is transmitted by mosquito bites. It can cause fevers, severe polyarthralgias (70-100% of cases) and polyarthritis (44-63% of cases). Chronic arthritis has been reported in 25% to 75% of cases. Chikungunya fever is endemic in parts of Western Africa but is also common in many regions of Asia. Maculopapular drug eruptions are the most common type of drug hypersensitivity reaction and are characterized by a generalised eruption of erythematous macules and/or papules after initiating drug therapy. Maculopapular drug eruptions are common side effects of cephalosporins. HSP is a small vessel leucocytoclastic vasculitis characterized by palpable purpura. The purpuric rash is typically symmetrical and located primarily in pressure dependent areas such as the lower extremities. Many cases of HSP are preceded by an upper respiratory tract infection such as Streptococcus but many other infectious agents have been implicated as possible triggers. Disclosure M.A. Lee: None.