The most common fungi to cause skin infections are the tinea group of fungi. For example, athlete's foot (tinea pedis) is a common fungal infection of the toes and feet. Tinea infection also causes ringworm (tinea corporis) and ringworm of the scalp (tinea capitis) . It also causes many fungal nail infections . A common fungal infection of the mouth and of the vagina is called thrush. This is caused by an overgrowth of candida which is a yeast (a type of fungus). Small numbers of candida commonly live harmlessly on the skin. However, certain conditions can cause candida to multiply and cause infection . Candida is also sometimes the cause of some fungal nail infections.
Corticosteroids are generally teratogenic in laboratory animals when administered systemically at relatively low dosage levels. The more potent corticosteroids have been shown to be teratogenic after dermal application in laboratory animals. There are no adequate and well controlled studies in pregnant women on teratogenic effects from topically applied corticosteroids. Therefore, topical corticosteroids should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Drugs of this class should not be used extensively on pregnant patients, in large amounts, or for prolonged periods of time.
Resistance to ketoconazole has been observed in a number of clinical fungal isolates, including Candida albicans . Experimentally, resistance usually arises as a result of mutations in the sterol biosynthesis pathway. Defects in the sterol 5-6 desaturase enzyme reduce the toxic effects of azole inhibition of the 14-alpha demethylation step. Multidrug-resistance (MDR) genes can also play a role in reducing cellular levels of the drug. As azole antifungals all act at the same point in the sterol pathway, resistant isolates are normally cross-resistant to all members of the azole family.