Recent studies have indicated that polarized light may be useful in the discrimination between benign and malignant moles. In fact, imaging polarimetry could provide noninvasive diagnosis of a range of dermatological disease states. However, in order to design an efficacious sensor for clinical use, the complete polarization-altering properties of a particular disease must be well understood. We present Mueller matrix imaging polarimetry as a technique for characterizing various dermatological diseases. Preliminary Mueller matrix imagery at 633 nm suggests that both malignant moles and lupus lesions may be identified through polarimetric measurements. Malignant moles are found to be less depolarizing than the surrounding tissue, and lupus lesions are found to have rapidly varying retardance orientation.