What Does the Skin Reveal about Psychiatric Disorders?
In what ways does the skin reveal brain changes? Perhaps the most important skin signs are seen with neuropsychiatric, addiction, pain and itch disorders.
Psychiatric disorders are central nervous system conditions with a neurobiological basis. They generally involve disturbances of emotion, cognition, motivation and socialization. Psychiatric disorders can either lead to psychocutaneous (skin) manifestations as a consequence or they may arise as a result of a chronic dermatological condition that impacts on the patient’s mental health.
What can be done about these troubling maladies? Treatment for neurodermatitis is multifocal. Initial treatment usually involves topical and systemic glucocorticoids. Glucocorticoids are used to decrease the itching and redness of affected areas. Additionally, treatment may be aimed at decreasing depression or any psychological ailments, if present. Counseling and Habit reversal therapy have been successful in encouraging cessation of scratching.
Several studies have been launched to find ways to quiet the discomfort of prurigo nodularis (PN). One is sponsored by Kiniksa Pharmaceuticals to investigate the efficacy and safety of vixarelimab (KPL-716) a monoclonal antibody administered subcutaneously that targets oncostatin M (OSM) receptor-beta (OSMRβ) to inhibit two cytokine signaling pathways, interleukin-31 (IL-31) and OSM. This potentially disrupts the pruritus, inflammation, hyperkeratosis and fibrosis associated with PN. Many cases of PN are associated with depression, and perhaps utilizing psychiatric interventions with new injectable treatments might provide relief.
What skin diseases reflect neuroendocrine dysfunction? Neurocutaneous disorders include tuberous sclerosis, ataxia-telangiectasia, and Sturge-Weber syndrome.
Although itching and pain sensations were at one time thought to be sent along the same nerve pathways, researchers reported the discovery in 2003 of itch-specific nerve pathways. Nerve endings that are specifically sensitive to itching have been named pruriceptors.
Pruritus (itch) starts with an external stimuli—dust, touch, a mosquito landing on your arm—and is a built-in defense mechanism that alerts your body to the potential of being harmed. If the stimuli goes over the threshold when it scratches your skin's surface layer, dermal skin receptors will send an immediate signal through fibers in the skin to your spinal cord and then up to the cerebral cortex in your brain that tells you to scratch. You may feel some relief when this itch response is temporarily interrupted, but a persistent itch may result in a chronic itch-scratch-itch cycle.
The term “itch” has evolved into many connotations in our society. Researchers have found that songs get stuck in our heads because they create a "brain itch" or “cognitive itch” analogous to histamines that make our brain itch and can only be scratched by repeating the tune over and over. Thus, “Who Let The Dogs Out?” is the aural equivalent of a skin itch that can drive you crazy.
Senile pruritus often refers to the dry skin of aging. I never liked that term, although it dates back to a time when the term senile had a more benign connotation, perhaps like misplacing your keys instead of feeling your mind slip into the shadows.
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