Miscellaneous Substances

Keratolytics are used to destroy unwanted tissue, including warts and corns. Great care is obviously necessary to avoid ulceration. They include trichloracetic acid, salicylic acid and many others. Resorcinol and sulphur are mild keratolytics used in acne.

Squalane is a saturated hydrocarbon insoluble in water but soluble in sebum. It therefore penetrates the skin and is a vehicle for delivery of agents; it is water repellent and is used for incontinence and prevention of bed sores. It appears in mixed formulations.

Salicylic acid may enhance the efficacy of a topical steroid in hyperkeratotoic disorders.

Tars are mildly antiseptic, antipruritic and they inhibit keratinisation in an ill-understood way. They are safe in low concentrations and are used in psoriasis. Photosensitivity occurs. There are very many preparations, which usually contain other substances, e.g. coal tar and salicylic acid ointment; it is sometimes useful to add an adrenal steroid.

Ichthammol is a sulphurous tarry distillation product of fossilised fish (obtained in the Austrian Tyrol); it has a weaker effect than coal tar.

Zinc oxide provides mild astringent, barrier and occlusive actions.

Calamine is basic zinc carbonate that owes its pink colour to added ferric oxide. It has a mild astringent action and is used as a dusting powder and in shake and oily lotions. It is of limited value.

Urea is used topically to assist skin hydration, e.g. in ichthyosis.

Insect repellents, e.g. against mosquitoes, ticks, fleas, such as deet (diethyl toluamide), dimethyl phthalate. These are applied to the skin and repel insects principally by vaporisation. They must be applied to all exposed skin, and sometimes also to clothes if their objective is to be achieved (some damage plastic fabrics and spectacle frames). Their duration of effect is limited by the rate at which they vaporise (skin and ambient temperature), by washing off (sweat, rain, immersion) and by mechanical factors causing rubbing (physical activity). They can cause allergic and toxic effects, especially with prolonged use. About 10% is absorbed. Plainly the vehicle in which they are applied is also important, and an acceptable substance achieving persistence of effect beyond a few hours has yet to be developed. But the alternative of spreading an insecticide in the environment causing general pollution and indiscriminate insect kill is unacceptable. Selective environmental measures against some insects, e.g. mosquitoes, are sometimes feasible.

Benzyl benzoate may be used on clothes; it resists one or two washings.

Was this article helpful?

0 0
Mole Removal

Mole Removal

Moles, warts, and other unsightly irregularities of the skin can be bothersome and even embarrassing. They can be removed naturally... Removing Warts and Moles Naturally! If you have moles, warts, and other skin irregularities that you cannot cover up affecting the way you look, you can have them removed. Doctors can be extremely expensive. Learn the natural ways you can remove these irregularities in the comfort of your own home.

Get My Free Ebook

Post a comment