Ondansetron Treatment in a Child Presenting with Chronic Intractable Pruritus

Abstract

The case of a seven-year-old boy with chronic pruritus secondary to a giant congenital melanocytic nevus is presented. The pruritus did not respond to conventional antipruritic drug treatment, but responded to ondansetron, a selective antagonist of 5-hydroxytryptamine type 3 receptors.Key Words: Children; Giant congenital melanocytic nevus; Ondansetron; Pruritus; Serotonin antagonist Un traitement à l'ondansétron pour un enfant atteint d'un prurit chronique réfractaire Est présenté le cas d'un garçon de sept ans atteint d'un prurit chronique secondaire à un naevus mélanocytique géant congénital. Le prurit n'a pas répondu à un traitement classique aux antipruritiques, mais a répondu à l'ondansétron, un antagoniste sélectif des récepteurs 5-hydroxytryptamine de type 3. O ndansetron is effective against chemotherapy-induced and postoperative nausea and vomiting (1,2). Over the past few years, several publications reported on the efficacy of ondansetron in treating neuraxial opioid-induced pruritus (3-5) and uremic pruritus in continuous ambulatory peritoneal dialysis (6). The current report presents a case of a child suffering from chronic pruritus refractory to conventional antipruritic drugs who was successfully treated with ondansetron. CASE PRESENTATIONA seven-year-old African-American boy weighing 21 kg was referred to the Chronic Pain Clinic at The Montreal Children's Hospital (Montreal, Quebec) with a history of disabling pruritus that was not responding to conventional treatment. The boy was born with a giant congenital melanocytic nevus with a bathing trunk distribution. The nevus was thick and was distributed from the mid-back to the buttocks with extension to the scrotum. The child had previously undergone several partial excisions of the nevus with skin grafts. Biopsies were regularly performed to evaluate the potential for malignancy. Multiple satellite nevi, that increased in number each year, covered his whole body including his face and scalp. In addition, he had three melanin-containing lesions in the brain. The brain lesions were stable and did not increase with time. The child also suffered from chronic constipation secondary to his bathing trunk nevus for which he was treated with lactulose, a colon lavage preparation (GoLYTELY, Braintree Laboratories Inc, Canada) and a high fibre diet.The patient had suffered from generalized pruritus and scratching since his first year of life. Different antipruritic treatments were tried over the years but with poor success. He was initially treated with antihistamines -hydroxyzine and diphenhydramine. Methotrimeprazine (Nozinan, sanofi aventis Canada Inc), a neuroleptic, was added to diphenhydramine for one year. Doxepin (Sinequan, ERFA Canada Inc), an antidepressant with antihistaminic properties, and ketotifen (Zaditen, PendoPharm, Canada), a noncompetitive inhibitor of histamine type 1 (H 1 ) receptors, also failed in relieving the pruritus. The pruritus did not improve with the application of local moisturizers and a topical antipruritic (Sarna P lotion,...

Skin of Patients with Large/Giant Congenital Melanocytic Nevi Shows Increased Mast Cells

“…Recently, this abnormality has been shown to be caused by somatic mutations in codon Q61 of NRAS [6], It is well known that mastocytes (MC) participate in allergic and inflammatory processes. In this context, we have previously reported an increased number of MC in a " bulky perineal nevocytoma" (a form of L/GCMN) of a 3-year-old girl who presented with intractable pruritus [7], Pruritus is a frequent symptom in patients with L/ GCMN and could be intense and difficult to control with medication [7,8]. In addition, MC and melanocytes derive from different progenitors but share regulation by stem cell factor (SCF).…”