Thermography and vasomotor test.

Vasomotor tests have a great diagnostic interest in many dermatologic diseases. Histamine dihydrochloride and acetylcholine chloride in intradermal injections, a rubefacient derived from nicotinic acid in epicutaneous application, and the dermograph are commonly used and studied here. There remain many unknown and controversial factors in the interpretation of the mechanisms of the drugs used for these tests. A thermographic approach using infrared thermography and the most recent technique with liquid crystals in sheet provide a new contribution to studies on vasomotor tests; these methods have contributed to the study of the vasomotor reactions observed in different dermatological affections, in particular atopic eczema, and have introduced new data in the controversy which subsists about interpretations of 'delayed cholinergic blanch'.