Chronic rubbing of the skin will frequently produce tiny papules which on closer examination are seen to surround hair follicles.

20. White dermographism/delayed blanch

This is a curious blanch phenomenon seen after stroking the skin in which the normal red line and flare of the non-atopic individual is quickly replaced with a white line and no flare. Another blanching reaction occurs when acetylcholine is injected following the development of the red flare. Both of these can be seen in eczematous skin affected with contact dermatitis, but are not diagnostic. There are also paradoxical vasomotor changes seen in response to acetylcholine, nicotinic acid esters, and histamine.

21. Influence of environmental/emotional factors

These factors appear to play a modifying role in the course of AD. The effects of emotions, extremes of temperature and humidity, as well as texture of clothing have all been documented with respect to AD patients. There is altered peripheral cutaneous vasoconstriction of affected skin in atopics with a decreased response to cooling and warmth and increased perspiration in the flexural regions.