Non-typical morphology and localization in Turkish atopic dermatitis patients with onset before the age of 18 years

Background: Hanifin and Rajka′s criteria (HRC) are the gold standard for the diagnosis of atopic dermatitis (AD). Apart from the age-related distribution and typical morphology of the lesions as defined in one of the major criteria of HRC, patients may also show nontypical morphology and localization. Aim: The aim of this study was to find the frequency of nontypical morphology and localization in Turkish AD patients with onset before the age of 18 years, who were diagnosed according to HRC. Methods: This was a methodological study based on the analysis of patients′ data derived from the checklists of HRC and precise clinical documentation of each patient. A total of 321 Turkish patients diagnosed between 1996 and 2004 with the onset of AD before the age of 18 years were allocated to the study group. Results: 49.5% of patients had nontypical localization of AD, the majority being infants or children who had flexural involvement rather than the typical cheek or extremity lesions. Lichenified/exudative eczematous pattern was the most frequent morphologic type (45.5%); however, 54.5% of the patients showed combined or isolated variants, e.g. nummular and seborrheic patterns, in particular. Conclusions: A considerable amount of Turkish patients with AD before the age of 18 years presented with nontypical morphology and/or localization according to their age group. The confirmation of our findings in a multicentric prospective study would further allow a completion and correction of the diagnostic criteria of AD for age groups.