|
Itching
Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itch leads to a scratch reflex. Unmyelinated nerve fibers for itch and pain both originate in the skin; however, information for them is conveyed centrally in two distinct systems that both use the same nerve bundle and spinothalamic tract. Classification Most commonly, an itch is felt in one place. If it is felt all over the body, then it is called ''generalized itch'' or ''generalized pruritus''. If the sensation of itching persists for six weeks or longer, then it is called ''chronic itch'' or ''chronic pruritus''. ''Chronic idiopathic pruritus'' or ''essential pruritus'' is a rare form of itch that persists for longer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antipruritic
Antipruritics, abirritants, or anti-itch drugs, are medications that inhibit the itching (Latin: ''pruritus'') often associated with sunburns, allergic reactions, eczema, psoriasis, chickenpox, fungal infections, insect bites and stings like those from mosquitoes, fleas, and mites, and contact dermatitis and urticaria caused by plants such as poison ivy (urushiol-induced contact dermatitis) or stinging nettle. It can also be caused by chronic kidney disease and related conditions. Abirritants consist of a large group of drugs belonging to different classes with varying mechanisms to treat itch. They may work either directly or indirectly to relieve itch, and evidence on their effectiveness varies from one class to another. Some alternative medicines are also used to treat itch. Side effects of abirritants also vary depending on the class of the drug. Even before the emergence of modern evidence-based medicine, abirritants have already been used in many civilizations, but practices ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dry Skin
Xeroderma, xerosis or xerosis cutis, or simply dry skin, is a skin condition characterized by excessively dry skin. The medical term ''xeroderma'', meaning "dry skin", derives from modern Latin, ''xero-'' 'dry' + Greek ''derma'' 'skin'. In most cases, dry skin can safely be treated with emollients or moisturizers. Xeroderma occurs most commonly on the scalp, lower legs, arms, hands, the knuckles, the sides of the abdomen, and thighs. Symptoms most associated with xeroderma are such skin conditions as scaling (the visible peeling of the outer skin layer), itching, and skin fissures (cracked skin). Causes Xeroderma is a very common condition. It happens more often in the winter when the cold air outside and the hot air inside creates a low relative humidity. This causes the skin to lose moisture and it may crack and peel. Bathing or hand washing too frequently, especially if one is using harsh soaps, can contribute to xeroderma. Xeroderma can be caused by a deficiency of vitami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutaneous Larva Migrans
Cutaneous larva migrans (abbreviated CLM) is a skin disease in humans, caused by the larvae of various nematode parasites of the hookworm family ( Ancylostomatidae). These parasites live in the intestines of dogs, cats, and wild animals and should not be confused with other members of the hookworm family for which humans are definitive hosts, namely ''Ancylostoma duodenale'' and ''Necator americanus''. Colloquially called creeping eruption due to its presentation, the disease is also somewhat ambiguously known as " ground itch" or (in some parts of the southern United States) "sandworms", as the larvae like to live in sandy soil. Another vernacular name is plumber's itch. The medical term CLM literally means "wandering larvae in the skin". Symptoms and signs The infection causes a red, intensely pruritic (itchy) eruption, and may look like twirling lesions. The itching can become very painful and if scratched may allow a secondary bacterial infection to develop. Cutaneous larva mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Louse
The body louse (''Pediculus humanus humanus'', also known as ''Pediculus humanus corporis'') is a hematophagic ectoparasite louse that infests humans. It is one of three lice which infest humans, the other two being the head louse, and the crab louse or pubic louse. Despite the name, body lice do not directly live on the host. They lay their eggs on fibres of clothing and only come into contact with the host whenever they need to feed. Since body lice cannot jump or fly, they spread by direct contact with another person or more rarely by contact with clothing or bed sheets that are infested. Body lice are disease vectors and can transmit pathogens that cause human diseases such as epidemic typhus, trench fever, and relapsing fever. In developed countries, infestations are only a problem in areas of poverty where there is poor body hygiene, crowded living conditions, and a lack of access to clean clothing. Outbreaks can also occur in situations where large groups of people a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scratch Reflex
The scratch reflex is a response to activation of sensory neurons whose peripheral terminals are located on the surface of the body.Stein, P. S. G. (1983). The vertebrate scratch reflex. Symposia of the Society for Experimental Biology(37), 383–403 Some sensory neurons can be activated by stimulation with an external object such as a parasite on the body surface. Alternatively, some sensory neurons can respond to a chemical stimulus that produces an itch sensation. During a scratch reflex, a nearby limb reaches toward and rubs against the site on the body surface that has been stimulated. The scratch reflex has been extensively studied to understand the functioning of biological neural network, neural networks in vertebrates. Despite decades of research, key aspects of the scratch reflex are still unknown, such as the neural mechanisms by which the reflex is terminated. Scratch reflex in dogs Most dogs will exhibit a scratch reflex when they are stimulated in the saddle re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scratch Reflex
The scratch reflex is a response to activation of sensory neurons whose peripheral terminals are located on the surface of the body.Stein, P. S. G. (1983). The vertebrate scratch reflex. Symposia of the Society for Experimental Biology(37), 383–403 Some sensory neurons can be activated by stimulation with an external object such as a parasite on the body surface. Alternatively, some sensory neurons can respond to a chemical stimulus that produces an itch sensation. During a scratch reflex, a nearby limb reaches toward and rubs against the site on the body surface that has been stimulated. The scratch reflex has been extensively studied to understand the functioning of biological neural network, neural networks in vertebrates. Despite decades of research, key aspects of the scratch reflex are still unknown, such as the neural mechanisms by which the reflex is terminated. Scratch reflex in dogs Most dogs will exhibit a scratch reflex when they are stimulated in the saddle re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phototherapy
Light therapy, also called phototherapy or bright light therapy is intentional daily exposure to direct sunlight or similar-intensity artificial light in order to treat medical disorders, especially seasonal affective disorder (SAD) and circadian rhythm sleep-wake disorders. Treating skin conditions such as neurodermatitis, psoriasis, acne vulgaris, and eczema with ultraviolet light is called ultraviolet light therapy. Medical uses Nutrient deficiency Vitamin D deficiency Exposure to light at specific wavelengths of Ultraviolet B (abbreviated as UV-B or UVB) enables the body to produce vitamin D to treat vitamin D deficiency. Skin conditions Light therapy treatments for the skin usually involve exposure to ultraviolet light. The exposures can be to a small area of the skin or over the whole body surface, as in a tanning bed. The most common treatment is with narrowband UVB, which has a wavelength of approximately 311–313 nanometers. Full body phototherapy can be de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atopic Dermatitis
Atopic dermatitis (AD), also known as atopic eczema, is a long-term type of inflammation of the skin (dermatitis). It results in puritis, itchy, red, swollen, and cracked skin. Clear fluid may come from the affected areas, which often thickens over time. While the condition may occur at any age, it typically starts in childhood, with changing severity over the years. In children under one year of age, much of the body may be affected. As children get older, the areas on the insides of the knees and elbows are most commonly affected. In adults, the hands and feet are most commonly affected. Scratching the affected areas worsens the symptoms, and those affected have an increased risk of skin infections. Many people with atopic dermatitis develop hay fever or asthma. The cause is unknown but believed to involve genetics, immune system dysfunction, environmental exposures, and difficulties with the Semipermeable membrane, permeability of the skin. If one identical twin is affected, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermatology
Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medical doctor who manages diseases related to skin, hair, nails, and some cosmetic problems. Etymology Attested in English in 1819, the word "dermatology" derives from the Greek δέρματος (''dermatos''), genitive of δέρμα (''derma''), "skin" (itself from δέρω ''dero'', "to flay") and -λογία '' -logia''. Neo-Latin ''dermatologia'' was coined in 1630, an anatomical term with various French and German uses attested from the 1730s. History In 1708, the first great school of dermatology became a reality at the famous Hôpital Saint-Louis in Paris, and the first textbooks (Willan's, 1798–1808) and atlases ( Alibert's, 1806–1816) appeared in print around the same time.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yawning
A yawn is a reflex lasting 4-7 seconds, and is characterized by a long inspiratory phase with gradual mouth gaping, followed by a brief climax (or acme) with muscle stretching, and a rapid expiratory phase with muscle relaxation. For fish and birds, this is described as gradual mouth gaping, staying open for at least 3 seconds and subsequently a rapid closure of the mouth. Almost all vertebrate animals, including mammals, birds, reptiles, amphibians, and even fish, experience yawning. The study of yawning is called chasmology. Yawning (oscitation) most often occurs in adults immediately before and after sleep, during tedious activities and as a result of its contagious quality. It is commonly associated with tiredness, stress, sleepiness, boredom, or even hunger. In humans, yawning is often triggered by the perception that others are yawning (for example, seeing a person yawning, or talking to someone on the phone who is yawning). This is a typical example of positive feedb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stimulus (physiology)
In physiology, a stimulus is a detectable change in the physical or chemical structure of an organism's internal or external environment. The ability of an organism or organ to detect external stimuli, so that an appropriate reaction can be made, is called sensitivity (excitability). Sensory receptors can receive information from outside the body, as in touch receptors found in the skin or light receptors in the eye, as well as from inside the body, as in chemoreceptors and mechanoreceptors. When a stimulus is detected by a sensory receptor, it can elicit a reflex via stimulus transduction. An internal stimulus is often the first component of a homeostatic control system. External stimuli are capable of producing systemic responses throughout the body, as in the fight-or-flight response. In order for a stimulus to be detected with high probability, its level of strength must exceed the absolute threshold; if a signal does reach threshold, the information is transmitted to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mirror Neuron
A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another. Thus, the neuron "mirrors" the behavior of the other, as though the observer were itself acting. Such neurons have been directly observed in human and primate species, and in birds. In humans, brain activity consistent with that of mirror neurons has been found in the premotor cortex, the supplementary motor area, the primary somatosensory cortex, and the inferior parietal cortex. The function of the mirror system in humans is a subject of much speculation. Birds have been shown to have imitative resonance behaviors and neurological evidence suggests the presence of some form of mirroring system. To date, no widely accepted neural or computational models have been put forward to describe how mirror neuron activity supports cognitive functions. The subject of mirror neurons continues to generate intense debate. In 2014, Philosophical Transactions o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_02.jpg "Click for more on -> Antipruritic")
