Clinical features of the extrinsic and intrinsic types of adult-onset atopic dermatitis

Abstract

BackgroundMost study concerning the prevalence and dermatological manifestations of the extrinsic and the intrinsic form of atopic dermatitis (AD) were performed in children and adult AD related to the early-onset AD extending to adult life. Adult-onset AD is a subgroup of AD. Apart from the typical eczematous flexural distribution pattern of AD, this group may also have nontypical morphology and localization.ObjectiveThe purpose of this study was to compare the clinical and diagnostic features of Thai patients with extrinsic and intrinsic type of adult-onset AD.MethodsWe retrospectively studied case records of patients diagnosed as adult-onset AD at the skin allergy clinic, Department of Dermatology, Siriraj Hospital, Mahidol University, Bangkok, Thailand from June, 2006 to May, 2008. The diagnosis of AD was made according to the criteria of Hanifin and Rajka and the severity of AD in each patient were assessed using the eczema area and severity index and the Rajka and Langeland score.ResultsFifty six patients were enrolled. Eighty-seven percent of patients were extrinsic AD (eAD). Females predominated in both groups. Patients with eAD more commonly had typical lichenified/exudative eczematous lesions, especially on the antecubital and popliteal areas, when compared with patients with intrinsic AD (iAD). Nummular and follicular lesions were more commonly seen in iAD group than the eAD group. The most common area of involvement in the iAD was non-flexural area, followed by flexural area and extensor area. The severity of both iAD and eAD did not show a significant difference.ConclusionThe eAD type of adult-onset AD was more common than the iAD type. Patients with eAD frequently had flexural lichenification whereas the iAD group tended to have nonflexural area involvement. The severity of both iAD and eAD did not show a significant difference.

Animal Models of Allergic Diseases

“…Although the intrinsic form has been considered by some as a step toward the development of extrinsic form, it is becoming increasingly clear that it may actually represent a different subtype [5]. No difference in severity of disease is typically observed between the two subsets of patients although different frequency in distribution of lesions has been described [7]. The intrinsic form tends to develop in older patients and filaggrin mutations are not a characteristic of this form [8].…”

Is there something called adult onset atopic dermatitis in India?

“…Fölster-Holst et al [13] and Brenninkmeijer et al [14] observed intrinsic AD to have a later age at onset and milder disease severity when compared to extrinsic AD. However, Kulthanan et al [12] found no difference in the disease severity between the two groups and both extrinsic and intrinsic AD had an early age at onset in their study. Thus intrinsic AD is uncommon in adults unlike in children.…”

“…[11] Extrinsic AD is more common in adult onset AD (87.5-93.05%) and the prevalence of intrinsic AD tends to be higher in younger individuals (15-45%) when compared to adults (5.4-12.5%). [12,13] This could probably be due to the delayed appearance of respiratory allergies signifying the atopic march in children, or it could be that some forms of intrinsic AD are triggered by sensitization to completely different antigens or it could be that very young children have a transient form of spontaneously resolving eczema that is not a typical AD.…”

“…In a study by Kulthanan et al, [12] the typical pattern of lichenified/exudative eczematous lesions on the antecubital and popliteal areas were more common among patients with extrinsic AD whereas nummular and follicular lesions were more common in patients with intrinsic AD. Also, non-flexural involvement was more common in intrinsic AD followed by flexural area and extensor area.…”

“…[2,12] However, some of the features of these criteria do not have much relevance in adults and diagnosing adult onset AD strictly based on these criteria would result in missing many cases of AD in adults. [2] Early age at the onset is one of the criteria, which is of no relevance in a case of adult onset AD.…”