Psychological aspects of atopic dermatitis

Atopic dermatitis is a chronic fluctuating skin disease which usually has an onset between two and six months after birth. During exacerbations, the lesions become widely disseminated; redness, oedema, weeping, crusting, excoriations, and fissures are the distinctive features. The pathogenesis of atopic dermatitis is not clearly understood. Genetic, environmental, physiological, immunological, and psychological factors have all been implicated. Emotional stress, personality structure, psychophysiological abnormalities, and learned behaviour have been advanced as mechanisms by which psychological factors affect atopic dermatitis. This thesis examines the first three of these areas. Retrospective interview studies have found that emotional stress precipitates exacerbations of atopic dermatitis in approximately 70% of cases but studies utilising life events and daily hassles as measures of stress have not found evidence of an association. In the first study reported of this thesis, 50 atopic dermatitis sufferers completed a daily diary for a fortnight, recording their emotional state and skin condition. Both self-report of interpersonal stress and depression were significantly related to changes in the skin condition. Lag sequential analyses indicated that interpersonal stress on Day X predicted skin condition on Day X+1 and that this relationship was reciprocal. The second study examined the relationship between stress and skin symptoms in 13 atopic dermatitis suffferers sitting university examinations. Again, a significantly positive relationship was found. A preliminary study of appraisal and coping processes associated with examinations was conducted utilising multiple regression analysis in order to determine their relationship to skin symptoms. The literature on the relationship between personality features and atopic dermatitis was reviewed and a meta-analysis of suitable studies conducted. Based on the results of this review and meta-analysis, a study was performed in which 50 atopic dermatitis sufferers recruited from the general community were compared to 20 subjects with ichthyosis; also from the community; and 35 skin disorder-free controls on a range of personality and emotional state measures. The atopic dermatitis sufferers were divided on the basis of whether subjects believed that stress affected their symptoms. The "nonstress" atopic dermatitis sufferers were found to score lower on neuroticism than all other groups. They also reported less trait anxiety, lower emotional dependence on others, and a more internal locus of control with regard to control over social systems than the "stress" atopic dermatitis sufferers. No other differences existed between the groups, with the exception of the fact that the ichthyosis sufferers were significantly more able to assert their autonomy, and less conforming in their responses to frustrating circumstances. However, the skin disorder control group was noted to have a higher level of neuroticism than published norms. The use of subjects recruited from the community and the moderate to high correlations between many of the measures were discussed in the interpretation of the results. In the final study, differences in autonomic nervous system reactivity were examined. Eleven atopic dermatitis sufferers were compared with ten age and sex matched controls on a number of tasks such as relaxation, a video game, and mental arithmetic. Reactivity on physiological variables such as heart rate, arm skin temperature, finger blood volume , and skin conductance level were assessed across the tasks. The atopic dermatitis sufferers were found to be more reactive on mental arithmetic, a task that is known to lead to sympathetic nervous system arousal. This finding is consistent with previous research. Further analysis indicated that the two groups displayed a different pattern of reactivity across time for finger blood volume and arm skin temperature, and a close to significant difference for heart rate. Of particular interest was the finding that the atopics showed a rise in skin temperature at the site of affected skin, while the controls showed a continued fall in temperature at a matched site. Therefore, this study provided partial support for the existence of increased sympathetic reactivity in atopic dermatitis as well as partial support for the existence of symptom specificity. Findings from all studies were integrated into past research as well as the three psychobiological conceptions of atopic dermatitis and Lipowski's biopsychosocial conception of psychosomatic medicine. Further extensions of this work were suggested