Preparations applied directly to the skin to treat skin infections and infestations
Topical anti-infective or antiparasitic skin preparations are used to prevent or treat a number of skin infections and infestations. These preparations contain an active ingredient, which is mixed with a cream, ointment, lotion, or detergent base. The preparations are easy to apply and are formulated so that the drug remains on the surface of the skin, where its effect is needed. Some preparations that are used to treat skin infections and infestations may themselves irritate or inflame the skin or result in an allergic reaction, and, if this occurs, treatment should be discontinued.
Topical treatments for skin infections include antiseptic preparations, which are effective against a wide range of micro-organisms; antibiotics, used to prevent or treat infection with bacteria; and antiviral drugs and antifungal drugs, used to treat viral and fungal infections respectively. Antiparasitic drugs are commonly used to treat skin infestations.
These preparations contain chemicals that kill or prevent the growth of microorganisms that can cause infection in damaged skin. Antiseptic solutions and creams can be bought over the counter. Antiseptic solutions are added to water and used to clean broken skin; creams should be applied to wounds after they have been thoroughly cleansed. Antiseptics are also included in some shampoos and soaps to prevent minor scalp and skin problems, but they are of doubtful benefit.
These drugs are used in topical preparations to treat bacterial infections of the skin, such as infected eczema or impetigo. Severe burns may also be treated with a topical antibiotic in order to prevent infection. In some cases, a preparation containing two or more antibiotics is used to make sure that all bacteria are eradicated. You should always follow your doctor’s instructions on how long to continue using a topical antibiotic preparation. Stopping early may allow a skin infection to recur.
Some topical antivirals used to treat conditions such as cold sores, which are caused by herpes viruses, can be bought over the counter. These drugs are most effective used early in an attack. Most common viral infections that cause a rash, such as rubella, do not need treatment, and many infections in the skin, such as warts, do not respond to topical antiviral drugs. However, herpes zoster and genital herpes are treated effectively with oral antivirals.
These drugs are used to treat fungal infections, including athlete’s foot, ringworm, thrush (see Vaginal thrush, and Oral thrush), and fungal nail infections (see Nail abnormalities). Treatment of nail infections may need to be continued for several months to allow healthy nail to grow. Some topical antifungals can be bought over the counter. However, some fungal infections do not respond to topical preparations and require treatment with oral drugs.
Infestations of head lice are treated with an antiparasitic lotion or cream rinse that is washed off later. For pubic lice, your doctor will prescribe a lotion or cream to apply to the pubic area. Scabies is treated with a lotion or cream applied all over the body and washed off after 8–24 hours. All members of a household affected by head lice or scabies should be treated at the same time to avoid reinfestation. In the case of infestation with pubic lice, sexual partners should be checked for lice and treated simultaneously if necessary.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.