**2. Case Report**

A four-year-old child presented to our department with lower limbs pain and refusal to walk, with legs fixed in flexion at hips and knees for about four months. The symptoms were partially managed with non-steroidal anti-inflammatory drugs (NSAIDs). Patient's mother did not refer fever, skin rash or weight loss. About familial history, his sister was healthy, his grandmother suffering from celiac disease and a first-grade cousin was affected from juvenile idiopathic arthritis (JIA) in therapy with NSAIDs. Patient was born at term with normal weight and length. His psychomotor development was referred in the norm up to seven–eight months of age, then patient presented a delay of psychomotor and language development. Dietary history reveals highly selective eating since the second year, based exclusively on ham and white meat homogenized, with refusal of fruits and vegetables. Since about one year the mother reports difficulty in eating, and several episodes of gingivitis with antivirals and topical antifungals with partial benefit. When patient came to our department he was in fair general conditions, his weight was 17 kg (25–50th) and his height was 105 cm (25–50th). The physical examination was difficult because of the patient's developmental delay, however it revealed pale and dry skin, corkscrew hair and signs of follicular hyperkeratosis in the lower and upper limbs. Child refused to walk, with legs fixed in flexion at hips and knees ("Frog leg-position"). Both legs were diffusely tender to palpation. The child was uncooperative for oral examination but erythematous, hemorrhagic, and swollen gums in maxillary anterior region were noted (Figure 1). The rest of physical examination was normal. Blood examinations revealed low iron and vitamin D level, while complete blood count, serum chemistries, liver and kidney, function panel, coagulation panel (prothrombin time, activated partial thromboplastin time, and international normalized ratio) and inflammatory parameters (C-reactive protein and erythrocyte sedimentation rate) were normal. Hips, knees and ankle ultrasound did not reveal joints effusion or signs of tenosynovitis. X-ray of the lower limbs (Figure 2) did not reveal fractures, but generalized osteopenia and typical features of malnutrition, including a ground glass appearance, Pelkan spur, which represents a healing metaphyseal pathologic fracture, and a Wimberger ring sign, which denotes a thin sclerotic cortex surrounding a lucent epiphysis. Periosteal reaction due to subperiosteal hemorrhage with a dense provisional calcification immediately adjacent to the physis (Frankel line), and an adjacent lucent band more diaphyseal in location (Trummerfeld line) were noted. In consideration

of the result of blood examinations and of the lower limbs X-ray, we hypothesized a state of nutritional deficiency. Furthermore, peculiar elements of both personal history and clinical examination, such as selective dietary habits, follicular hyperkeratosis, corkscrew hair, relapsing gingivitis and joint pain in the absence of signs of local inflammation led to the diagnostic hypothesis of vitamin C deficiency. This clinical suspicion was confirmed by the finding of low levels serum vitamin C < 2.4 μmol/L (normal value 26.1–84.6). Supplementary treatment with oral vitamin C (300 mg daily) and D (800 UI daily) was started. Patient clinical condition improved with recovery of walking and an oral clinical healing of the gingival enlargement (Figure 3). One month after discharge, the boy had normal vitamins' levels: 35.6 μmol/l (normal value 26.1–84.6).

**Figure 1.** First oral clinical presentation (T0).

**Figure 2.** Lower limb X-ray showing typical features such as radio-dense band (Frenkel line), marginal spur formation.

**Figure 3.** Oral tissues healing presentation after four weeks of Vitamin C administration (Tf).
