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Year : 2003  |  Volume : 69  |  Issue : 6  |  Page : 421-422

Urea ointment (40%)

MK Shah 
 Hon. Dermatologist, Bhatia General Hospital, Mumbai, India

Correspondence Address:
M K Shah
402, Sugan, 13, Cumballa Hill Lane, August Kranti Marg, Mumbai - 400036

How to cite this article:
Shah M K. Urea ointment (40%).Indian J Dermatol Venereol Leprol 2003;69:421-422

How to cite this URL:
Shah M K. Urea ointment (40%). Indian J Dermatol Venereol Leprol [serial online] 2003 [cited 2020 Aug 9 ];69:421-422
Available from: http://www.ijdvl.com/text.asp?2003/69/6/421/6632

Full Text

Urea ointment (40%) is a tissue softener that has been used under occlusion for the chemical avulsion of nails and for the treatment of palmoplantar keratoderma.[1] It is not effective for the avulsion of normal nails (non-dystrophic nails).[1] It can also be used topically for the treatment of calluses.

 40% Urea ointment

Urea 40 g

Anhydrous lanolin 20 g

White wax 5 g

White petrolatum 35 g

The patient is asked to cover the normal skin surrounding the affected nail plate with Micropore tape. Urea ointment is then smoothed onto the nail surface, which is then covered with a piece of plastic film wrap. This is then covered with a layer of Micropore tape. The patient is instructed to keep the area completely dry using plastic gloves and to return after 5 to 10 days. The treated nails are then removed by cutting away the abnormal portions using a bone spatula and a nail cutter. This is followed by curettage until clinically normal nail is reached at all margins.

For the treatment of onychomycosis, 40% urea ointment is ideally combined with oral or topical antifungal agents such as bifonazole 1% cream.[2],[3],[4],[5]

When using bifonazole in combination, the patient is asked to apply 1% bifonazole cream and 40% urea ointment under occlusion to the affected nails during the first phase of treatment. This is renewed every 24 hours after elimination of the cellular debris with a plastic spatula. This treatment is continued for 15 days. During the second phase, 1% bifonazole cream is applied every day for 6 weeks.[6]

Forty percent urea ointment may help remove hypertrophic or dystrophic psoriatic nails. Subsequent topical therapy to the denuded nail bed and proximal nail fold can result in regrowth of nail folds.[6]



Urea is soluble in water and alcohol, and has marked hydrating properties. It attracts and holds water, resulting in transepidermal water migration. High concentrations of urea dissolve proteins and can be used as a denaturant.[7] The ability of urea to macerate dystrophic nails has been attributed to a 'proteolytic effect',[8] but others attribute the maceration to the hydrating properties of urea.[9]


Hydrous wool fat is a purified fat-like substance of sheep, with a water content of 25-30%. Anhydrous lanolin is lanolin that contains not more than 0.25% of water. Lanolin has been used as an emollient and protective in the past, but is used sparingly nowadays because of its sensitization potential.

White petrolatum

Petrolatum is a white unctuous mass obtained from crude oil, consisting of hydrocarbons. It is messy, with a tendency to leak through bandages.

White wax

White wax is obtained from the honeycomb of trees. It consists of esters of monohydric alcohols esterified with fatty acids. Its role appears to be to stiffen the formulation so that it does not spread to the surrounding skin.


Irritation and erosive dermatitis may occur. Use of urea in excoriated or fissured skin can produce stinging and irritation. These adverse effects are related to the high acidity of the preparations (usually pH 3 or less).[10]


Forty percent urea is a valuable adjunct along with oral or topical antifungal agents for treating onychomycosis. Chemical avulsion with 40% urea ointment is essentially painless and apparently without risk of infection or hemorrhage, which is advantageous for treating patients with diabetes mellitus and others with vascular insufficiency and neuropathy of the digits.

The combination of 40% urea ointment with 1% bifonazole cream is a useful option in those with a contraindication for or unwilling to use oral antifungal agents. The combination seems appealing for treating children and the elderly, in whom the side effects of oral antifungals would be a valid concern.

There have been no studies comparing the efficacy of antifungal nail lacquers like 8% ciclopirox olamine or 1% amorolfine vs. 40% urea ointment with or without 1% bifonazole. But it appears that nail lacquers are more suitable for treating the more superficial onychomycoses, and as maintenance therapy to prevent recurrence after successful treatment of onychomycosis.


1Farber EM, South DA. Urea ointment in the nonsurgical avulsion of nail dystrophies. Cutis 1978;22:689-92.
2Hardjoko FS, Widyanto S, Singgih I. Treatment of onychomycosis with a bifonazole-urea combination. Mycoses 1990;33:167-71.
3Friedman-Birnbaum R, Cohen A, Shemer A, Bitterman O, Bergman R, Stettendorf S. Treatment of onychomycosis: A randomized double-blind comparison study with topical bifonazole-urea ointment alone and in combination with short-duration oral griseofulvin. Int J Dermatol 1997;36:67-9.
4Tsuboi R, Unno K, Komatsuzaki H, Ogawa H, Kasai T, Oka K, et al. Topical treatment of onychomycosis by occlusive dressing using bifonazole cream containing 40% urea. (Article in Japanese. Source: Pubmed) Nippon Ishinkin Gakkai Zasshi. 1998;39:11-6.
5Bonifaz A, Ibarra G. Onychomycosis in children: Treatment with bifonazole-urea. Pediatr Dermatol 2000;17:310-14.
6Arndt KA, Bowers KE. Manual of dermatologic therapeutics. Philadelphia: Lippincott, Williams & Williams; 2002.
7Ashton H, Frank E, Stevens CJ. Urea as a topical agent. Br J Dermatol 1971;84:194-6.
8Port M, Sanicola KF. Nonsurgical removal of dystrophic nails utilizing urea ointment occlusion. J Am Podiatry Assoc 1980;70:521-3.
9Pinner TAF, Jones RH, Bandisode MS. Study of efficacy of urea compound versus emollient cream in avulsive therapy of dystrophic nails. Cutis 1990;46:155-7.
10Banerjee PK, Choudhary AK, Panja SK. Topical urea in dermatology. Indian J Dermatol 1990;36:17-25.


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