Purpura Fulminans: A Rare Manifestation of Indian Tick Typhus

Sir, A 48-year-old female patient presented to us with complaints of a low-grade fever and bleeding from the nose and gums for 3 days. General physical examination was normal. Dermatologic evaluation revealed multiple purpuric, nonpruritic rashes in both the palms and lower limbs [Figure 1a] with gangrenous changes in the right thumb, left index finger, and the second and third toes of both the left and right lower limbs [Figure 1b and c].Figure 1: (a) Pruritic rash in bilateral lower limbs, (b) gangrenous digits of both feet, (c) gangrenous fingers and purpuric rash on both palmsThe patient was started on antipyretics, intravenous ceftriaxone, and enoxaparin 40 mg subcutaneously 12 hourly. Laboratory investigations were as follows: hemoglobin – 11.01 g/dl, total leukocyte count – 15,000/mm3, and platelet – 47,000/mm3; all other routine investigations such as liver function test, renal functions tests, and coagulation profile were normal. Antinuclear antibody profile, cytoplasmic antineutrophilic cytoplasmic antibody, and complement C3 and C4 were negative. Blood serology for malarial parasite, dengue, Leptospira, and scrub typhus was negative. A Weil–Felix test result indicated a significant titer for Ox-2 (1:80) positive, Ox-19 (1:80) positive, and OXK antigen (1:40) negative, which confirmed the diagnosis of rickettsial disease due to Rickettsia conorii. The patient was started on injection doxycycline 100 mg iv bd. On the 4th day of doxycycline treatment, the patient became afebrile. From the 5th day onward, the purpuric rash started to fade. The gangrenous changes remained static. Injection enoxaparin was stopped on the 7th day. Doxycycline was stopped after 7 days. The patient was discharged on the 10th day. Acute infectious purpura fulminans is a medical emergency associated with skin necrosis and purpuric rash.[1,2] Infections such as malaria, dengue, meningococcemia, and rickettsial fever can cause purpura fulminans. The Weil–Felix test confirmed the diagnosis of this case as R. conorii (Indian tick typhus). W-F test is the oldest assay based on detecting antibodies to various Proteus antigens that cross-react with rickettsia.[3,4] The W-F test detects IgM antibody that is detectable 5–10 days following the onset of symptoms. Strain differentiation helped us diagnose Indian tick typhus sepsis rickettsial disease due to R. conorii. The drug of choice for Indian tick typhus is doxycycline, which, on administration patients, showed relative symptomatic improvement.[5] Research quality and ethics statement The authors followed applicable EQUATOR Network (https://www.equator-network.org/) guidelines, notably the CARE guideline, during the conduct of this report. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.