Antipruritic

Antipruritics, also known as 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.

Common antipruritics

Topical antipruritics in the form of creams and sprays are often available over the counter. Oral anti-itch drugs also exist and are usually prescription drugs. The active ingredients usually belong to these classes:

• Antihistamines such as diphenhydramine (Benadryl)
• Corticosteroids such as hydrocortisone topical cream, see topical steroid
• Counterirritants, such as mint oil, menthol, or camphor^[1]
• Local anesthetics such as lidocaine and benzocaine topical creams
• Nalfurafine, an orally-administered, centrally-acting κ-opioid receptor agonist approved for uremic pruritus and effective in animal models of other prurituses^[2]

Disputed and questionable antipruritics

• Burow's solution, an astringent aqueous solution of aluminium acetate, is shown to soothe and to relieve itching.
• Olive oil
• Jewelweed has been shown to be devoid of any anti-itch activity in several controlled studies ^[3][4][5][6]
• Selective serotonin reuptake inhibitor are a class of medicines commonly used for depression, and are also said to be effective in controlling pruritus in a small number of refractory cases.^[7] Mirtazapine, a different type of antidepressant, also has antipruritic effects due to its strong antagonism of the H₁ receptor.
• Calamine lotion, containing zinc oxide and iron(III) oxide, is a traditional remedy for mild itching, such as that typically associated with chicken pox – although the U.S. Food and Drug Administration has asserted that it has little if any effect.^[8][9]
• Paste of sodium bicarbonate (baking soda) and water, applied topically^[10]
• Ammonium hydroxide (household ammonia), applied topically^[10] (However it can relieve some kinds of insect stings which itch, such as mosquito bites, by neutralizing an acid component of the sting.)
• Papain-based topical creams.

Home remedies

• Cooling with ice or cold water (usually stops the itch for as long as the ice or cold water is applied)
• Slightly painful stimulation such as rubbing, slapping, scratching, or heating based on a spinal antagonism between pain- and itch-processing neurons
• Pine tree gum applied to the affected areas for short periods of time can help in drawing out the oils and drying the skin.
• Frequent washing of the affected areas in hot water with a drying soap removes oils that come to the surface as the blisters form and provides temporary relief from itching.
• Applying emollients to the skin such as baby oil or petroleum jelly after showering

References

1. Hercogová J (2005). "Topical anti-itch therapy". Dermatologic therapy 18 (4): 341–3. doi:10.1111/j.1529-8019.2005.00033.x. PMID 16297007.
2. Inui, Shigeki (2015). "Nalfurafine hydrochloride to treat pruritus: a review". Clinical, Cosmetic and Investigational Dermatology: 249. doi:10.2147/CCID.S55942. ISSN 1178-7015.
3. D. Long, N. H. Ballentine, J. G. Marks. Treatment of poison ivy/oak allergic contact dermatitis with an extract of jewelweed. Am. J. Contact. Dermat. 8(3):150-3 1997 PMID 9249283
4. M. R. Gibson, F. T. Maher. Activity of jewelweed and its enzymes in the treatment of Rhus dermatitis. J. Am. Pharm. Assoc. Am. Pharm. Assoc. 39(5):294-6 1950 PMID 15421925
5. J. D. Guin, R. Reynolds. Jewelweed treatment of poison ivy dermatitis. Contact Dermatitis 6(4):287-8 1980 PMID 6447037
6. Zink, B. J.; Otten, E.J.; Rosenthal, M.; Singal, B (1991). "The Effect Of Jewel Weed In Preventing Poison Ivy Dermatitis". Journal of Wilderness Medicine 2 (3): 178–182. doi:10.1580/0953-9859-2.3.178. Retrieved 2008-01-16.
7. Lee CS, Koo J (2005). "Psychopharmacologic therapies in dermatology: an update". Dermatologic clinics 23 (4): 735–44. doi:10.1016/j.det.2005.05.015. PMID 16112451.
8. "American Topics. An Outdated Notion, That Calamine Lotion". Archived from the original on 19 June 2007. Retrieved 2007-07-19.
9. Appel, L.M. Ohmart and R.F. Sterner, Zinc oxide: A new, pink, refractive microform crystal. AMA Arch Dermatol 73 (1956), pp. 316–324. PMID 13301048
10. Paul Tawrell, Wilderness Camping and Hiking(Falcon Distribution, 2008), 212.

External links

• Frontiers in pruritus research: scratching the brain for more effective itch therapy J. Clin. Invest. 116:1174–1185 (2006). DOI 10.1172/JCI28553