Vitamin C Deficiency Presenting as an Acute Limp in Childhood.

A previously well three-year-old boy attended with right knee pain and an antalgic gait. There was no history of fever and bloods including inflammatory markers were normal. A diagnosis of transient synovitis (irritable hip) was made and managed conservatively. One month later, he represented with increasing pain, now localising to his left hip, waking him at night with difficulty weight-bearing. No effusion was seen on ultrasound and bloods remained normal. He was discharged home but came back a week later with worsening polyarticular pain, a new maculopapular rash, significant bruising and new dental decay. A clinical diagnosis of vitamin C deficiency was made secondary to dietary insufficiency, and this was confirmed on blood testing. Within six weeks, his symptoms had fully improved on oral ascorbic acid (vitamin C) and he was engaging in dietetic input and reward systems to maintain a more balanced diet.