Seborrheic dermatitis (SD) is a common dermatologic disorder with a characteristic facial distribution. It occurs most commonly on the scalp, nasolabial folds, external ear canal, and on the hair-bearing areas of the face. The reason that lesions occur in this particular distribution is not known. Theories concerning the etiology of this distribution involve increased sebum production and implications of Pityrosporon ovale as a causative agent. In the course of evaluating the results of analysis with a very sensitive thermal imager, we were struck by a marked regional variation in the temperature of facial skin. The warmer areas of the face were those commonly affected by seborrheic dermatitis. These findings suggest that skin temperature plays a role in the etiology of SD. The following study was conducted to formally examine and confirm this relationship.
Hale EK, Bystryn J. Relation Between Skin Temperature and Location of Facial Lesions in Seborrheic Dermatitis. Arch Dermatol. 2000;136(4):559-560. doi: