PATH 232 Lecture Notes - Lecture 25: Keloid, Irritant Diaper Dermatitis, Posterior Grey Column
1 Dec 2018
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Disorders of skin lecture 24: functions of skin: 3 layers of skin. epidermis, dermis, subcutaneous layer. Lesions: loss of normal tissue continuity, struct. or fn. Primary: happens in previously normal skin: ie freckles, moles. Rashes: area where skin has become swollen, inflamed or irritated. Caused by chemicals called pruritogens: histamine, serotonin, cytokines, bradykinin, bile salts, opioids, substance p. exacerbated by inflammation, dry or heat, skin vasodilation, stressors. *itching sensation transmission: originates within the skin"s free nerve endings, is carried by small myelinated type c nerve fibers to dorsal horn of spinal cord and transmitted to somatosensory cortex. 2. neurogenic: results from things that affect other organs leading to release of pruritogens and an itching sensation sensed by cns. 3. neuropathic: lesions in cns that block normal response. Or relieve itch via topical anti itch cream, apply ice, systemic antihistamines like. Can be due to aging, or from systemic diseases such as dermatitis. Severe pruritus: most commonly on extremities, back abdomen or waist.
