Itch: Difference between revisions
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Itch | {{SI}} | ||
{{Infobox medical condition | |||
| name = Itch | |||
| image = [[File:Itch_01.jpg|250px]] | |||
| caption = A person scratching an itch | |||
| field = [[Dermatology]] | |||
| synonyms = Pruritus | |||
| symptoms = [[Sensation]] of the skin that provokes the urge to [[scratch]] | |||
| complications = [[Skin infection]], [[scarring]] | |||
| onset = Can be sudden or gradual | |||
| duration = Varies; can be acute or chronic | |||
| causes = [[Allergy|Allergic reactions]], [[skin conditions]], [[insect bites]], [[systemic disease]] | |||
| risks = [[Dry skin]], [[eczema]], [[psoriasis]], [[liver disease]], [[kidney disease]] | |||
| diagnosis = [[Physical examination]], [[medical history]], [[blood test]] | |||
| differential = [[Pain]], [[tingling]], [[burning sensation]] | |||
| treatment = [[Moisturizers]], [[antihistamines]], [[corticosteroids]], [[phototherapy]] | |||
| medication = [[Antihistamines]], [[topical steroids]], [[capsaicin cream]] | |||
| frequency = Very common | |||
| deaths = Rarely life-threatening | |||
}} | |||
[[File:Itch 01.jpg|left|thumb|Itch]] | |||
[[File:Scabies-burrow.jpg|thumb|Scabies burrow]] | |||
[[File:CercariaDermatitis.jpg|left|thumb|Cercaria Dermatitis]] | |||
[[File:Tinea pedis interdigitalis.jpg|left|thumb|Tinea Pedis Interdigitalis]] | |||
[[File:Squirrel Scratching the Armpit with its Hindlimb.jpg|left|thumb|Squirrel Scratching]] | |||
[[File:Canis lupus scratching.jpg|thumb|Wolf Scratching]] | |||
[[File:Lioness (Panthera leo) scratching ... (52016987141).jpg|left|thumb|Lioness Scratching]] | |||
Itch, also known as pruritus, is an unpleasant sensation that provokes the desire to scratch. It is a common symptom associated with a variety of dermatological conditions and systemic diseases. Understanding the mechanisms and causes of itch is crucial for effective management and treatment. | Itch, also known as pruritus, is an unpleasant sensation that provokes the desire to scratch. It is a common symptom associated with a variety of dermatological conditions and systemic diseases. Understanding the mechanisms and causes of itch is crucial for effective management and treatment. | ||
==Pathophysiology== | ==Pathophysiology== | ||
Itch is a complex sensory phenomenon that involves the skin, peripheral nerves, and central nervous system. The sensation of itch is primarily mediated by specific nerve fibers known as C-fibers, which are also involved in the transmission of pain. These fibers are activated by various pruritogens, which are substances that induce itching. | Itch is a complex sensory phenomenon that involves the skin, peripheral nerves, and central nervous system. The sensation of itch is primarily mediated by specific nerve fibers known as C-fibers, which are also involved in the transmission of pain. These fibers are activated by various pruritogens, which are substances that induce itching. | ||
The pathophysiology of itch involves several key components: | The pathophysiology of itch involves several key components: | ||
* '''[[Peripheral Mechanisms]]''': Itch receptors in the skin are activated by pruritogens such as histamine, which is released by mast cells in response to allergens or irritants. Other mediators include proteases, cytokines, and neuropeptides. | * '''[[Peripheral Mechanisms]]''': Itch receptors in the skin are activated by pruritogens such as histamine, which is released by mast cells in response to allergens or irritants. Other mediators include proteases, cytokines, and neuropeptides. | ||
* '''[[Central Mechanisms]]''': Once the itch signal is transmitted to the spinal cord, it is relayed to the brain, where it is processed in areas such as the somatosensory cortex. The central processing of itch involves complex interactions between various neurotransmitters and neural pathways. | * '''[[Central Mechanisms]]''': Once the itch signal is transmitted to the spinal cord, it is relayed to the brain, where it is processed in areas such as the somatosensory cortex. The central processing of itch involves complex interactions between various neurotransmitters and neural pathways. | ||
* '''[[Neuroimmune Interactions]]''': The immune system plays a significant role in the sensation of itch. Inflammatory mediators released during immune responses can enhance the sensitivity of itch receptors and contribute to chronic itch conditions. | * '''[[Neuroimmune Interactions]]''': The immune system plays a significant role in the sensation of itch. Inflammatory mediators released during immune responses can enhance the sensitivity of itch receptors and contribute to chronic itch conditions. | ||
==Causes== | ==Causes== | ||
Itch can be classified into several categories based on its underlying cause: | Itch can be classified into several categories based on its underlying cause: | ||
* '''[[Dermatological Causes]]''': Conditions such as atopic dermatitis, psoriasis, and contact dermatitis are common causes of itch. These conditions often involve inflammation and disruption of the skin barrier. | * '''[[Dermatological Causes]]''': Conditions such as atopic dermatitis, psoriasis, and contact dermatitis are common causes of itch. These conditions often involve inflammation and disruption of the skin barrier. | ||
* '''[[Systemic Causes]]''': Systemic diseases such as liver disease, kidney failure, and certain cancers can cause generalized itch. This is often due to the accumulation of pruritogenic substances in the body. | * '''[[Systemic Causes]]''': Systemic diseases such as liver disease, kidney failure, and certain cancers can cause generalized itch. This is often due to the accumulation of pruritogenic substances in the body. | ||
* '''[[Neuropathic Itch]]''': Damage to the nervous system, such as in multiple sclerosis or post-herpetic neuralgia, can lead to neuropathic itch. | * '''[[Neuropathic Itch]]''': Damage to the nervous system, such as in multiple sclerosis or post-herpetic neuralgia, can lead to neuropathic itch. | ||
* '''[[Psychogenic Itch]]''': Psychological factors, including stress and anxiety, can exacerbate or even cause itch in the absence of a physical stimulus. | * '''[[Psychogenic Itch]]''': Psychological factors, including stress and anxiety, can exacerbate or even cause itch in the absence of a physical stimulus. | ||
==Diagnosis== | ==Diagnosis== | ||
Diagnosing the cause of itch involves a thorough clinical evaluation, including a detailed history and physical examination. Laboratory tests, skin biopsies, and imaging studies may be necessary to identify underlying systemic conditions or dermatological disorders. | Diagnosing the cause of itch involves a thorough clinical evaluation, including a detailed history and physical examination. Laboratory tests, skin biopsies, and imaging studies may be necessary to identify underlying systemic conditions or dermatological disorders. | ||
==Treatment== | ==Treatment== | ||
The treatment of itch depends on its underlying cause. General measures include: | The treatment of itch depends on its underlying cause. General measures include: | ||
* '''[[Topical Treatments]]''': Emollients, corticosteroids, and calcineurin inhibitors can help reduce inflammation and soothe the skin. | * '''[[Topical Treatments]]''': Emollients, corticosteroids, and calcineurin inhibitors can help reduce inflammation and soothe the skin. | ||
* '''[[Systemic Treatments]]''': Antihistamines, immunosuppressants, and biologics may be used for more severe or systemic causes of itch. | * '''[[Systemic Treatments]]''': Antihistamines, immunosuppressants, and biologics may be used for more severe or systemic causes of itch. | ||
* '''[[Non-Pharmacological Approaches]]''': Behavioral therapies, phototherapy, and acupuncture have been used to manage chronic itch. | * '''[[Non-Pharmacological Approaches]]''': Behavioral therapies, phototherapy, and acupuncture have been used to manage chronic itch. | ||
==Also see== | ==Also see== | ||
* [[Dermatitis]] | * [[Dermatitis]] | ||
| Line 43: | Line 52: | ||
* [[Nervous system]] | * [[Nervous system]] | ||
* [[Immune system]] | * [[Immune system]] | ||
[[Category:Dermatology]] | [[Category:Dermatology]] | ||
[[Category:Symptoms]] | [[Category:Symptoms]] | ||
[[Category:Neurology]] | [[Category:Neurology]]]] | ||
Revision as of 04:23, 14 April 2025
Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD medical weight loss NYC and sleep center NYC
| Itch | |
|---|---|
| File:Itch 01.jpg | |
| Synonyms | Pruritus |
| Pronounce | N/A |
| Specialty | N/A |
| Symptoms | Sensation of the skin that provokes the urge to scratch |
| Complications | Skin infection, scarring |
| Onset | Can be sudden or gradual |
| Duration | Varies; can be acute or chronic |
| Types | N/A |
| Causes | Allergic reactions, skin conditions, insect bites, systemic disease |
| Risks | Dry skin, eczema, psoriasis, liver disease, kidney disease |
| Diagnosis | Physical examination, medical history, blood test |
| Differential diagnosis | Pain, tingling, burning sensation |
| Prevention | N/A |
| Treatment | Moisturizers, antihistamines, corticosteroids, phototherapy |
| Medication | Antihistamines, topical steroids, capsaicin cream |
| Prognosis | N/A |
| Frequency | Very common |
| Deaths | Rarely life-threatening |
_scratching_..._(52016987141).jpg)
Itch, also known as pruritus, is an unpleasant sensation that provokes the desire to scratch. It is a common symptom associated with a variety of dermatological conditions and systemic diseases. Understanding the mechanisms and causes of itch is crucial for effective management and treatment.
Pathophysiology
Itch is a complex sensory phenomenon that involves the skin, peripheral nerves, and central nervous system. The sensation of itch is primarily mediated by specific nerve fibers known as C-fibers, which are also involved in the transmission of pain. These fibers are activated by various pruritogens, which are substances that induce itching. The pathophysiology of itch involves several key components:
- Peripheral Mechanisms: Itch receptors in the skin are activated by pruritogens such as histamine, which is released by mast cells in response to allergens or irritants. Other mediators include proteases, cytokines, and neuropeptides.
- Central Mechanisms: Once the itch signal is transmitted to the spinal cord, it is relayed to the brain, where it is processed in areas such as the somatosensory cortex. The central processing of itch involves complex interactions between various neurotransmitters and neural pathways.
- Neuroimmune Interactions: The immune system plays a significant role in the sensation of itch. Inflammatory mediators released during immune responses can enhance the sensitivity of itch receptors and contribute to chronic itch conditions.
Causes
Itch can be classified into several categories based on its underlying cause:
- Dermatological Causes: Conditions such as atopic dermatitis, psoriasis, and contact dermatitis are common causes of itch. These conditions often involve inflammation and disruption of the skin barrier.
- Systemic Causes: Systemic diseases such as liver disease, kidney failure, and certain cancers can cause generalized itch. This is often due to the accumulation of pruritogenic substances in the body.
- Neuropathic Itch: Damage to the nervous system, such as in multiple sclerosis or post-herpetic neuralgia, can lead to neuropathic itch.
- Psychogenic Itch: Psychological factors, including stress and anxiety, can exacerbate or even cause itch in the absence of a physical stimulus.
Diagnosis
Diagnosing the cause of itch involves a thorough clinical evaluation, including a detailed history and physical examination. Laboratory tests, skin biopsies, and imaging studies may be necessary to identify underlying systemic conditions or dermatological disorders.
Treatment
The treatment of itch depends on its underlying cause. General measures include:
- Topical Treatments: Emollients, corticosteroids, and calcineurin inhibitors can help reduce inflammation and soothe the skin.
- Systemic Treatments: Antihistamines, immunosuppressants, and biologics may be used for more severe or systemic causes of itch.
- Non-Pharmacological Approaches: Behavioral therapies, phototherapy, and acupuncture have been used to manage chronic itch.
