SUPERFICIAL MYCOSES

by DrChika

Superficial mycoses are fungal infections which are only limited to the keratinized outer layer of the skin, hair and nails. Superficial mycoses unlike other forms of mycoses rarely result in inflammatory reactions in the host but it is usually characterized by intense itching and peeling or scaling of the affected body sites. They are self-limiting mycoses and benign in their action. Superficial mycoses are non-systemic fungal infections that only infect the surface layer of the skin, and they are usually associated to poor personal hygiene amongst people.

Fungal organisms that cause superficial mycoses are the least known penetrating or invasive fungal species that cause mycoses in humans (Table 1). This is because they only colonize the keratinized outer layer of the skin especially the malpighian layer of the epidermis- which contains keratinocytes that produces the protein keratin, and they generally have no systemic or invasive effect on the body during or after prior infection with the causative agents.

Superficial mycoses are contagious mycoses, and thus it can be transferred or spread in a defined human population via direct body contact with infected persons. People who share personal items of infected individuals such as bathing soap and towels or bed sheaths are at risk of catching superficial mycoses. Though most superficial mycoses are self-limiting and can heal on their own even without formal treatment, they can best be treated through a careful removal of the affected scalp of the skin or infected hairs and nails.

Subcutaneous mycosis is common amongst children, adolescents and young people who may occasionally experience some level of poor personal hygiene in their lifetime especially during their early development. However, the disease is normally localized in underdeveloped or developing countries especially in places where personal and public hygiene is poor; and both children and adults are easily infected. Topical antifungal agents can be applied in some cases to hasten the healing process of the infection and thus inhibit fungal growth in the affected body sites.

Table 1. Synopsis of superficial mycoses

MycosesCausative agentClinical featureSite of infection
    
Black piedraPiedraia hortaiBlack piedra is a chronic but mild fungal infection characterized by the adherence of hard black nodules to infected hairs especially at the hair shaft.Hairs of the scalp
    
White piedraTrichosporon beigeliiWhite piedra unlike black piedra is characterized by the adherence of soft & gelatinous larger white nodules to infected hairs including those of the pubic regions, scalp and beard. Arthroconidia are usually present in the hair shaft of affected hairs.Hairs of the scalp, pubic region and beard
    
Pityriasis or Tinea versicolorMalassezia speciesPityriasis versicolor is a chronic but mild fungal infection characterized by the invasion of the skin especially the cornified layer. There is also production of pigmented macula on the skin especially at the chest and back regions.Face, back, chest and arms  
    
Tinea nigraHortaea (Exophiala) werneckiiTinea nigra is a chronic but asymptomatic fungal infection of the stratum corneum (i.e. the layer of dead keratinized cells of the epidermis which progressively falls off). It is characterized by brown to black discolouration of the outer skin layer especially those of the palms. Palm

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