Mycoses or fungal infections in man can affect the most superficial layers of the skin giving rise to “superficial cutaneous-mucosa mycosis”, to deep layers in the so-called “deep mycosis” and finally some of these can spread and affect internal organs giving rise to “systemic mycoses”. Fortunately, these last two are rare in people with normal defenses, so we will only refer to the first.
The most frequent superficial mycoses in Spain are Pityriasis Versicolor, Dermatophytosis, and Candidiasis.
It is an asymptomatic infection of the most superficial layers of the skin caused by a yeast called Malassezia. They are yeasts with a great tendency to localize in oily areas of the skin such as the scalp, trunk, and folds. Its growth is favored in conditions of heat, humidity, sweating, and in situations of lowering of defenses, becoming pathogenic. It affects men more often than women, between the ages of 15 and 30, especially in the summer months.
It appears as round, well-defined spots with fine scales on their surface that come off with scratching. The color varies between brown, orange-pink, and white, becoming more apparent when we are exposed to the sun. The most common location is the thorax, shoulders, arms, abdomen, back, and neck, being very rare in the extremities and face. When cured, the surface is smooth, without flakes, light in color for several months and until the patient is exposed to the sun again. This condition is very easy to treat with a high cure rate, however, recurrences are frequent.
Dermatophytosis or ringworms
They are the result of infection of the skin, hair, and nails by fungi called dermatophytes, which feed on keratin. There are 3 genera of dermatophytes: Microsporum, Epidermophyton, and Trichophyton.
Some of them are only found in the human body, so the contagion occurs between people; others affect animals (dogs, cats, rabbits, and cattle) even, sometimes, they can be found in the ground and man is infected by coming into contact with them.
Ringworms appear as skin lesions with a central area of normal skin with a scaly border of centrifugal growth. Depending on the location, it gives rise to several clinical forms:
• Tinea capitis: It mainly affects children and results from the invasion of the hair shaft by dermatophytes.
• Ringworm of the beard: Infection of the hairy areas of the face and neck.
• Tinea corporis: circular lesions with well-defined and scaly edges.
• Tinea pedis: Infection of the sole and/or the interdigital spaces of the feet. It is very common in adults.
• Tinea cruris: Inguinal and/or perineal location in men.
• Tinea manum: Diffuse palmar hyperkeratosis, unilateral or bilateral.
• Tinea facei: Affects hairless areas of the face.
• Onychomycosis: Infection of the lateral and/or distal edges, the involvement of the entire nail plate, superficial white onychomycosis, proximal onychomycosis.
They are diseases of the skin and mucous membranes caused by yeast fungi belonging to the genus Candida. The species most frequently implicated is Candida Albicans.
Between 30-50% of people have the fungus in the mouth or digestive tract as part of their commensal flora and in 20% of women, it is part of their vaginal flora.
In certain circumstances, the balance between the organism and the fungus is broken, becoming at that moment pathogenic.
Among the factors that favor a yeast infection are:
• Local factors: humidity, maceration, occlusion.
• Physiological factors: infant and elderly, pregnancy, premenstrual phase.
• Pathological factors: endocrine diseases (diabetes, Addison’s disease, hypoparathyroidism), hematological diseases (lymphomas, leukemias), debilitating diseases, immunosuppression situations. • Medications: antibiotics, corticosteroids, immunosuppressants, and contraceptives.
Depending on the affected area we can find several clinical situations:
• Involvement of folds (armpits, groin, intergluteal, submammary, interdigital …) giving rise to itching or small vesicles that break and give rise to shiny red patches with a varnished appearance on both sides of the fold.
• Mouth: it is observed especially in children and immunosuppressed as creamy whitish membranes that cover the entire mucosa and are dislodged with scraping, leaving a red, congestive and bleeding surface.
• Corner of the mouth (angular cheilitis): inflammation of the mouth corners generally symmetrical with a fissure in the fundus. Its appearance is also influenced by dental prostheses and excess salivation.
• Onixis and peritonitis: it is the inflammation of the skin located around the nail and the nail itself with pain, erythema, and edema of said areas with secondary involvement of the nail that is favored by humidity.
For the treatment of all these infections, a large number of drugs called antifungal drugs, both topical and oral, are available, all of them highly effective. Among the topics, the imidazole derivatives, terbinafine, naphthyphin, cyclopyroxolamine, amorolfine tolnaftate, nystatin, and amphotericin stand out. Oral ones include griseofulvin, itraconazole, terbinafine, fluconazole, and ketoconazole.