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This chapter reviews the spectrum of cutaneous yeast infections caused by Candida and Malassezia yeasts, both of which are frequent commensal organisms on human hosts. Candida behaves as an opportunistic pathogen, producing fairly characteristic patterns of inflammatory skin, mucosal, and nail infection, with the potential to produce invasive and sometimes life-threatening disseminated disease. Malassezia, by contrast, produces several superficial cutaneous patterns is rarely a culprit in systemic disease.
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AT-A-GLANCE
Candida species produce a variety of inflammatory mucosal and cutaneous manifestations.
Favored areas of involvement include the oral mucosa and lips, fingers and nails, intertriginous zones, and genitalia.
A variety of conditions can predispose patients to chronic mucocutaneous candidiasis with diffuse skin, mucosal, and nail involvement.
Candida can cause invasive disease, including bloodstream infection, and is the most common culprit in fatal fungal sepsis.
Risk factors for infection include extremes of age, malnutrition, obesity, diabetes, and immune deficiency.
In mucocutaneous disease, morphology can be very helpful in making a clinical diagnosis, although confirmatory testing with potassium hydroxide preparations, culture, and histopathology (and in invasive disease, serology and polymerase chain reaction) also may be helpful.
Treatment includes topical imidazoles and nystatin, and in more-severe disease, systemic agents, including oral azoles and echinocandins.
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Candida yeasts are found throughout the environment and are also common commensals of the human skin, oropharyngeal, respiratory, GI, and genital mucosa. Candidal colonization has been reported in the oral mucosa of more than 40% of healthy adults, with higher rates of carriage in women and smokers.1 At least 15 of the more than 200 Candida species have been implicated in human disease. Although Candida albicans is the most commonly implicated Candida species in localized mucocutaneous candidiasis, an increasing number of other species have been implicated in mucocutaneous disease, including Candida glabrata, Candida tropicalis, Candida krusei, Candida parapsilosis, and Candida dubliniensis. Additionally, while albicans is still the single most common species, non-albicans species collectively now account for the majority of invasive candidiasis and candidemia.2 Other specific risk factors for infection are described below (see section “Risk Factors”).
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Localized Candida infection in the skin classically presents as beefy-red patches and plaques with satellite papules and pustules at the periphery (Fig. 161-1). Intertriginous areas, particularly the axillae, inframammary folds, groin folds, and infrapannus area, are frequently affected, and maceration may be an additional feature in these sites (Fig. 161-2A, B). Candida also may be implicated in miliaria arising on occluded skin surfaces, manifesting as small monomorphous vesicles (Fig. 161-3). On oropharyngeal mucosal surfaces, background erythema with adherent whitish material may be seen, as in the pseudomembranous form of oropharyngeal candidiasis (thrush) (Fig. 161-4A, D), however an erythematous form, characterized by a shiny depapillated lingual ...