There are many underlying causes that can lead to itch including skin diseases,
systemic diseases, neuropathic disorders, and psychological conditions. The
type of treatment depends on accurate identification of the root cause. Some of
the major types of pruritus include:
- Atopic dermatitis or eczema: A chronic inflammatory skin condition that is
one of the most common causes of itch, especially in children and young adults.
- Contact dermatitis: An allergic reaction caused by contact with certain
products, chemicals, plants, etc. Contact with poison ivy, nickel, fragrances
are common triggers.
- Psoriasis: A long-lasting autoimmune condition characterized by silvery
scales on the skin. The scales and plaques in psoriasis are often itchy.
- Urticaria or hives: Raised, itchy welts on the skin that come and go quickly
in flares. Hives can be triggered by food, medications, insect bites.
- Prurigo nodularis: Chronic itchy nodules and papules on the skin that develop
due to repeated scratching.
Neuropathic Pruritus
Itch can also arise from diseases affecting the somatosensory nerves like
shingles or postherpetic neuralgia. Diabetes, liver disease, kidney disease can
induce itch by causing neuropathy. Treatment of the underlying cause along with
medicines targeting sensory neurons are effective for neuropathic pruritus.
Newer options like tapentadol have shown promise in relieving diabetic neuropathy
related itch.
Topical Therapeutics
Mild to moderate itch is often effectively managed with
Pruritus
Therapeutics applied directly to the skin. Emollients and moisturizers
help reduce dryness and scaliness to decrease itch. Topical corticosteroids are
commonly prescribed as they reduce inflammation and itching. Calcineurin
inhibitors like pimecrolimus and tacrolimus have minimal side effects and treat
itch from eczema and psoriasis. Antihistamines are used in urticaria and
allergic rashes. Novel topical formulations of agents like menthol, capsaicin,
glycopyrrolate target itch sensation directly via TRP ion channels on nerve
endings.
Oral Therapeutics
For more severe, widespread, or persistent itch that does not respond to
topical treatments, oral therapies may be required. Antihistamines are again
first line for many cases. As second generation non-sedating options,
fexofenadine, levocetirizine, desloratadine are well-tolerated. Gabapentin and
pregabalin, originally anticonvulsants, act on calcium channels to relieve itch
from varied dermatological, hepatic and renal conditions. If caused due to
systemic inflammation, immunosuppressants like methotrexate may help itch from
rheumatoid arthritis or psoriasis. Psychotropics like mirtazapine, naltrexone,
and selective serotonin reuptake inhibitors alleviate itch in some patients via
effects on the somatosensory pathways.
Newer Targeted Therapies
Research has expanded understanding of neural pathways and molecular targets
involved in itch sensation and transmission. Newer biologic therapies blocking
specific pruritogens and their receptors show promise. For moderate-severe
atopic dermatitis, monoclonal antibodies against IL-4, IL-13 (dupilumab), IL-31
(nemolizumab), IL-22 (fezakinumab) have proven highly effective at reducing
inflammation and itch. Similarly, inhibitors against nerve growth factor (NGF)
have demonstrated benefit for atopic dermatitis and cholestatic pruritus. As
science unravels the complex neuroimmune interactions driving itch, we expect
development of novel, targeted therapeutics capitalizing on these discoveries.
Combined with advances in personalized medicine, this will enable optimizing
therapies tailored to individual patients’ clinical characteristics and disease
pathophysiology.
Scratching Behaviors and Psychosocial Management
Chronic itch leads to scratching which becomes habitual over time. Though
temporary relief is provided, chronic scratching causes excoriations, wounds,
infections and scarring which aggravates itching in a vicious cycle. Learning
to reduce or redirect scratching impulses is an important part of therapy.
Behavioral modifications, relaxation techniques, topical anesthetics before
scratching, padded gloves to reduce intensity if scratching occurs.
Psychological counseling helps address any anxiety, depression, stress
exacerbating itch or interfering with treatment adherence. Support groups for
patients and caregivers help share coping strategies. A multidisciplinary
treatment strategy combining pharmacologic therapies, behavioral interventions
and psychosocial support often yields the best outcomes in pruritus management.
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