Cutaneous mycoses

Cutaneous mycoses infections of the skin, hair, or nails are recurring presentations in the geriatric primary care setting. The most common infections are those caused by dermatophytes. The genus Trichophyton gives rise to most of the tinea dermatophytoses, including tinea capitis, tinea pedis, and tinea unguium (cutaneousmycoses). Part of the diagnostic challenge lies in distinguishing the mycotic lesions from those caused by cutaneous diseases such as psoriasis, eczema, dyshidrosis, and contact dermatitis. Because environmental conditions play a major role in fungal infection onset, clinical management should include patient education about conditions conducive to fungal propagation. Oral agents are the primary mode of treatment for fungal infections of the scalp and nails, whereas topical treatments are frontline agents for other superficial skin conditions. Most fungi live harmlessly in the environment, but some species can cause disease in the human host. Nurses working in primary care are likely to see patients with superficial fungal infections and are well placed to offer advice about treatment and measures to prevent the spread of infection in the home.

Introduction

Fungi belong to a diverse group of organisms that includes yeasts, moulds and dermatophytes (fungi that cause parasitic skin disease in humans) (Wilson 2006). They are classified in a separate kingdom from animals, plants and bacteria, and physiologically have most in common with animals. Most fungi live harmlessly in the environment, especially in soil and decaying matter, but approximately 200 species can cause disease in the human host (Wilson 2006). Fungal infections are not usually serious in otherwise fit, healthy adults, but they can be embarrassing and distressing. Very ill and immunocompromised patients are at risk of serious fungal infections, especially if they have had multiple courses of antibiotics and have undergone invasive procedures (Alberti et al, 2001). Exogenous infection (cross-infection) caused by fungi can occur from one patient to another at home and in healthcare settings. Fungi can cause healthcare-associated infections (HCAIs) and outbreaks have been reported in the UK and other developed countries (Wilson 2006). More than 300,000 species of fungi have been identified, but most live harmlessly in the environment where they play an important role, breaking down and recycling organic material from dead animals and plants. Only a few species are pathogenic. Saprophytes are organisms that live freely in the environment, obtaining their nutrients from dead or decaying animals and plants. Most fungi are saprophytic, as are many bacteria. Parasites obtain their nutrients and shelter from another living organism which is called the host. All viruses and some species of bacteria are obligate parasites, meaning that they are unable to live without a host, but no known species of fungi are obligate parasites. Commensals are organisms adapted to live on the skin and mucous membranes of the host and form part of its normal flora. They do not usually cause infection but have the capacity to operate as pathogens if the immune system is compromised.

Many fungal infections of the skin involve fungi that are found in the normal skin microbiota. Some of these fungi can cause infection when they gain entry through a wound; others mainly cause opportunistic infections in immune compromised patients