Teste de contato em crianças com diagnóstico clínico de dermatite atópica

Abstract

Atopic Dermatitis (AD) is a chronic and relapsing inflammatory skin disease that mainly affects children. Pathophysiology includes skin barrier dysfunction, immunological changes, and genetic factors. Allergic Contact Dermatitis (ACD) is also an inflammatory skin disease, and, unlike AD, it results from direct exposure to an external agent. Theoretically the impaired skin barrier facilitates the penetration of potential allergens and therefore AD patients may have an associated ACD. As eczema is similar in both conditions, it is important to perform a Patch Test (PT) for the differential diagnosis. The aim of this research was to identify the presence of ACD in pediatric patients with mild, moderate and severe AD at the IPPMG/UFRJ outpatient clinic. Twenty-six AD patients were tested, of which 23 (88.5%) had a positive PT for at least one allergen and 14 (53,8%) were polysensitized. The main allergens that tested positive were nickel nine (34,6%), blue disperse eight (30,8%), fragrance mix seven (26,9%), neomycin six (23,1%), cobalt chloride five (19,2%), thimerosal five (19,2%) and potassium bichromate five (19,2%). Of the tested patients, 21 (80.7%) had a clinically relevant PT and 19 (73%) tested positive for substances contained in therapeutic or skincare products. The data underscore the importance of performing PT in children with AD, especially in cases of recalcitrant dermatitis or with atypical distribution. The expressive percentage in the tests of allergens present in products for therapeutic purposes, indicates the constant need to review the proposed treatments. A specific and expanded PT battery, including also a negative control (vaseline), for pediatric AD patients increases the sensitivity for the diagnosis of ACD.