Blunted cortisol responses to psychosocial stress in asthmatic children: a general feature of atopic disease?

OBJECTIVE

Atopy is defined by the individual predisposition to develop a group of inflammatory disorders in response to certain food or environmental substances that are otherwise innocuous for the host. In previous studies we could demonstrate a reduced responsiveness of the hypothalamus-pituitary-adrenal (HPA) axis to psychosocial stress in young and adult patients with atopic dermatitis (AD), a chronic atopic skin disorder. With respect to the important immunoregulatory role of the HPA axis, especially under stress, this observation could be of clinical relevance and may at least partly explain stress-induced exacerbation of AD. The present study was designed to investigate whether attenuated responsiveness of the HPA axis to stress represents a characteristic feature of AD or whether it can also be found in other chronic manifestations of atopy.

METHODS

Children (aged 7-12) with allergic asthma (AA; N = 17) and age- and sex-matched healthy controls (N = 18) were exposed to the "Trier Social Stress Test for Children"(TSST-C), which mainly consists of a free speech and mental arithmetic tasks in front of an audience. Salivary cortisol was measured in ten-minute intervals before and after the TSST-C, while heart rate was monitored continuously. In addition, early morning cortisol levels (after awakening, +10, +20, +30 minutes) were assessed on three consecutive days.

RESULTS

Data analysis yielded a significant increase of cortisol concentrations (F (9297)= 16.79; p <.001) and heart rates (F(32,992)= 9.16; p <.001) after the stressor with no between-group difference in heart rate responses. However, AA children showed a significantly blunted cortisol response to the TSST-C when compared with the control group (F(9297)= 2.95; p <.01). Awakening in the morning was accompanied by a significant rise of cortisol levels on all three experimental days in AA and control subjects (all p <.001) that was not different between the two groups.

CONCLUSIONS

These findings suggest that a blunted adrenocortical response to stress may represent a common feature of chronic allergic inflammatory processes that may be relevant in different forms of chronic manifestation of atopy.