**Background:** Retiform purpura (RP) is a cutaneous manifestation of dermal and subcutaneous vascular compromise, caused either by vessel wall damage (vasculitides, infections, depositional diseases) or lumen occlusion (thrombosis, hypercoagulable states, platelet disorders, emboli). It presents as branching purpuric patches that can progress to necrosis and ulceration. RP can clinically mimic cutaneous small-vessel vasculitis (CSVV) or pyoderma gangrenosum but is distinguished by the absence of palpable purpura (CSVV) or marked purulence (pyoderma gangrenosum). The association between inflammatory bowel disease (IBD) and a hypercoagulable state is recognized but incompletely understood, involving interplay between hyperactive coagulation, decreased natural anticoagulants, abnormal fibrinolysis, endothelial dysfunction, chronically activated platelets, and systemic inflammation. This case report describes RP as the presenting feature of previously unrecognized IBD.
**Methods:** This is a single-patient case report from a tertiary care pediatric hospital. The patient underwent serial clinical examinations, laboratory evaluations (complete blood count, inflammatory markers, coagulation studies, liver enzymes, autoantibodies, infectious and rheumatologic workups), imaging (MRI), sequential cutaneous punch biopsies with direct immunofluorescence, endoscopy with colonoscopy and histopathology, and liver biopsy. Wound care and medical management were documented over a 3-month follow-up period.
**Key Results:** A 7-year-old girl with sickle cell trait presented with inability to bear weight and a painful rash on the right leg. Examination showed retiform purpura with tenderness that had worsened despite cephalexin. Family history was unremarkable. No fevers or other skin involvement were noted. Laboratory findings included microcytic anemia, elevated ESR, mildly elevated transaminases, and normal INR, albumin, and creatine kinase. MRI showed no muscle, bone, or joint involvement. Sequential cutaneous punch biopsies revealed superficial and deep mixed perivascular and interstitial dermatitis without thromboses or leukocytoclastic vasculitis. Direct immunofluorescence was nonspecific. Hematologic evaluation showed normal protein C and S levels with mildly elevated d-dimer. Rheumatologic and infectious evaluations were unremarkable. Over subsequent weeks, new purpuric patches appeared, some developing central duskiness and necrosis. She was noted to have mild colitic symptoms (PUCAI score 25), elevated fecal calprotectin, persistently elevated transaminases, and positive antinuclear antibody. Endoscopy and colonoscopy revealed gross pancolitis with erythema, edema, friability, and microhemorrhages. Histopathology showed chronic active colitis with cryptitis and abnormal crypt branching without granulomata. Liver biopsy confirmed autoimmune hepatitis. Treatment with systemic steroids improved her pain and transaminases, but the rash continued to evolve over 3 months, developing a central necrotic eschar with surrounding ulceration to the subcutaneous tissue that slowly healed with supportive wound care.
**Clinical Implications:** This case demonstrates that retiform purpura can be the presenting manifestation of underlying inflammatory bowel disease, even before gastrointestinal symptoms become prominent. Clinicians should consider IBD in the differential diagnosis of unexplained RP, particularly when standard hematologic, rheumatologic, and infectious workups are unrevealing. The vaso-occlusive process underlying RP in IBD likely reflects the complex interplay between coagulation and systemic inflammation. Treatment should address the underlying IBD (e.g., systemic steroids) combined with supportive wound care, though cutaneous healing may lag behind systemic improvement by months.