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Selling a Product or Service
FUNGAL SKIN INFECTIONS
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IHAB YOUNIS, M.D.
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• At one time it was thought that fungi were plants
  that did not need photosynthesis
• But now fungi are classified in their own
  kingdom, separate from plants and animals
  because
• 1- The cell walls of plants are made of
  cellulose whereas the walls of fungal cells are
  made of chitin
• 2- Plants require only simple inorganic
  compounds such as carbon dioxide and water to
  grow. Fungi require a diet of complex organic
  molecules to thrive

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• Fungi may be broadly divided into two basic
  forms, moulds and yeasts
• Moulds are made up of long
• multinucleate filaments called
• hyphae
• Yeasts are unicellular, made up of ovoid to
  globose cells which usually reproduce by budding

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• Dermatophytes are fungi that can cause infections
  of the skin, hair, and nails
• They colonize the keratin and inflammation is
  caused by host response to metabolic by-products

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• The organisms are transmitted by either direct
  contact with infected host (human or animal) or
  by direct or indirect contact with infected
  exfoliated skin or hair in combs, hair brushes,
  clothing, furniture, theatre seats, caps, bed
  linens, towels, hotel rugs, and locker room
  floors
• Depending on the species, the organism may be
  viable in the environment for up to 15 months

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Classification of dermophytes according to habitat

• Anthropophilic dermatophytes are restricted to
  human hosts and produce a mild, chronic
  inflammation
• Zoophilic organisms are found primarily in
  animals and cause marked inflammatory reactions
  in humans who have contact with infected cats,
  dogs, cattle, horses, birds, or other animals.
• Geophilic species are usually recovered from the
  soil but occasionally infect humans and animals.
  They cause a marked inflammatory reaction, which
  limits the spread of the infection and may lead
  to a spontaneous cure but may also leave scars

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• The main 3 genera of dermatophytes are
• Trichophyton
• Epidermophyton
• Microsporum

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• Classification of fungal skin diseases

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A. Superficial mycoses

• Infections limited to the outermost layers of
  the skin and hair
• Pityriasis versicolor
• Candidiasis 
• Tinea nigra 
• Black piedra
• White piedra 

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B. Cutaneous mycoses

• Infections that extend deeper into the epidermis,
  as well as hair and nail and caused by
  dermatophytes
• Tinea capitis
• Tinea corporis 
• Tinea manus
• Tinea cruris
• Tinea pedis
• Tinea unguium

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C. Subcutaneous mycoses

• Infections involving the dermis, subcutaneous
  tissues, muscle fascia
• Sporotrichosis 
•  Chromoblastomycosis 
•  Mycetoma 

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D. Systemic mycoses

• Infections that originate primarily in the lung
  and may spread to many organs

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Tinea Versicolor
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Etiology

• Malassezia furfur (Syn. Pityrosporon orbiculare,
  Pityrosporon ovale, and Malassezia ovalis)
• A member of normal human cutaneous flora, and it
  is found in 18 of infants and 90-100 of adults
• The condition is more noticeable during the
  summer months

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• In patients with clinical disease, the organism
  is found in both the yeast (spore) stage and the
  filamentous (hyphal) form
• Factors that lead to the conversion to the
  parasitic, mycelial morphologic form include a
  genetic predisposition warm, humid environments
  immuno-suppression malnutrition and Cushing
  disease

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• Prevalences reported to be as high as 50 in the
  humid, hot environment and as low as 1.1 in the
  colder temperatures
• The condition is not considered to be contagious
  because the causative fungal pathogen is a normal
  inhabitant of the skin
• Its occurrence before puberty or after age 65
  years is uncommon

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• The reason why this organism causes tinea
  versicolor in some individuals while remains as
  normal flora in others is not entirely known
• Several factors, such as the organism's
  nutritional requirements and the host's immune
  response to the organism, are significant

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• Evidence has been accumulating to suggest that
  amino acids (rather than lipids as previously
  thought) are critical for the appearance of the
  diseased state
• In vitro, the amino acid asparagine stimulates
  the growth of the organism, while glycine induces
  hyphal formation
• In vivo, the amino acid levels have been shown to
  be increased in the uninvolved skin of patients
  with tinea versicolor

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• Lymphocyte function on stimulation with the
  organism has been shown to be impaired in
  patients who are affected

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Clinically

• Numerous, well-marginated, finely scaly,
  oval-to-round macules
• Scattered over the trunk and/or the chest, with
  occasional extension to the lower part of
• the abdomen,
• the neck, and
• the proximal
• extremities

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• The macules tend to coalesce, forming irregularly
  shaped patches

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• As the name versicolor implies, the color of each
  lesion varies from almost white to reddish brown
  or fawn colored

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• An inverse form also exists affecting the
  flexural regions, the face, or isolated areas of
  the extremities
• This form is more often seen in hosts who are
  immunocompromised

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Cutaneous Candidiasis
Etymology Latin, feminine of candidusClear
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Etiology

• Candida albicans yeasts are unicellular fungi
  that typically reproduce by budding, a process
  that entails pinching off of the mother cell
• It has the ability to exist in both hyphal and
  yeast forms (dimorphism)
• If pinched cells do not separate, a chain of
  cells is produced and is termed pseudohyphae

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• Candidal species are part of the normal commensal
  flora throughout the gastrointestinal tract
  (mouth through anus)
• The vagina also is commonly colonized by yeast
  (13 of women), most commonly by C albicans
• Removal of bacteria from the skin, vagina and
  gastrointestinal tract results in reduced
  environmental and nutritional competition that
  favors the growth of candidal organisms

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Incidence increased due to

• Postnatal acquisition has been attributed to
  increased survival rates of low birth weight
  babies in association with an increased number of
  invasive procedures
• Older adults are more likely to be exposed to
  situations that increase the risk of invasive
  candidiasis, including treatment with
  broad-spectrum antibiotics , poor self-care, and
  decreased salivary flow

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• The use of broad spectrum antibiotics, and
  treatment with cytotoxic agents (eg,
  methotrexate, cyclophosphamide) for dermatologic
  and rheumatic conditions or aggressive
  chemotherapy for malignancy

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Clinical Types
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Candidal vulvovaginitis

• This common condition in women presents with
  itching, soreness, and a thick creamy white
  discharge
• Although most candidal infections occur more
  frequently with advancing age, vulvovaginitis is
  unusual in older women. In the absence of
  estrogen stimulation, the vaginal mucosa becomes
  thin and atrophic, producing less glycogen.
  Candidal colonization of vaginal mucosa is
  estrogen dependent and subsequently decreases
  sharply after menopause

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• Erythema of vaginal mucosa and vulval skin
• Curdy white flecks within the discharge
• Erythema may spread to include the
• perineumgroin
• with satellite
• pustules
• Alternatively, the
• vaginal mucosa
• may appear
• red and glazed

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Candidal balanitis

• Signs and symptoms of this candidal infection
  vary but may include tiny papules, pustules,
  vesicles, or persistent ulcerations on the glans
  penis
• Exacerbations following intercourse are common

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Oropharyngeal candidiasis (oral thrush)

• Acquired from the infected maternal mucosa
• during passage of the infant through the birth
• canal
• Lesions become visible as pearly white patches
• Buccal epithelium, gums, and the palate are
  involved with extension to the tongue, pharynx,or
  esophagus in more severe cases
• If the lesions are scraped away, an erythematous
  base is exposed. Lesions may progress to
  symptomatic erosion and ulceration

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Oral candidiasis in adults

• In older adults, the development of oral thrush
  in the absence of a known etiology should raise
  the clinician's index of suspicion for an
  underlying cause of immunosuppression, such as
  malignancy or AIDS
• With denture stomatitis, the areas of erythema
  may be painful and may affect up to 65 of
  patients who wear dentures

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• Occurs as white plaques that are present on the
  buccal, palatal, or oropharyngeal mucosa
  overlying
• areas of
• mucosal
• erythema

• Typically, the lesions are easily removed
  may show areas with tiny ulcers

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• In addition, some patients may develop soreness
  and cracks at the lateral angles of the mouth
  (angular cheilitis)
• Denture stomatitis presents as chronic mucosal
  erythema typically beneath the
• site of a denture

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Candidal diaper dermatitis

• 85-90 of infants with OPC harbor C albicans in
  the intestine and feces and in most patients, CCD
  is the result of progressive colonization from
  oral and gastrointestinal candidiasis

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Factors predisposing to infection

• -Infected stools
• -Macerated moist skin
• -Local irritation of the skin by friction
• -Ammonia from bacterial breakdown of urea
• -Intestinal enzymes
• -Detergents and disinfectants

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• Maceration of
• the anal mucosa
• and the perianal
• skin often is the
• first clinical
• manifestation
• Usually it starts in
• the perianal area,
• spreading to involve the perineum and, in
  severe cases, the upper thighs, lower abdomen,
  and lower back

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• The typical eruption begins
• with scaly papules that
• merge to form well-defined,
• weeping, eroded lesions
• with a scalloped border
• A collar of overhanging
• scales and an erythematous
• base may be demonstrated
• Satellite flaccid vesico-
• pustules around the primary
• intertriginous plaque also
• are characteristic

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Intertrigo

• Most cases occur in skin folds where occlusion
  (by clothing or shoes) produces abnormally moist
  conditions
• Other sites include the perineum, mouth, and
  anus, in which Candida organisms normally may be
  carried
• Candidal infection of the skin under the breasts
  occurs when those areas become macerated

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• Erythema, cracking, and maceration with soreness
  and pruritic symptoms
• Lesions typically have an irregular margin with
  surrounding satellite papules and pustules

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• Web spaces of affected
• fingers or toes are
• macerated and have
• the appearance of soft
• white skin, which is a
• condition termed
• erosio interdigitalis blastomycetica

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Paronychia

• Candida species (not always C albicans) can be
  isolated from most patients
• Bacteria also may act as copathogens
• Immediate contact dermatitis to food allergens
  may play a role
• Disease is more common in people who frequently
  submerge their hands in water and in diabetics

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• The nailfold becomes erythematous, swollen, and
  tender, with an occasional discharge
• Loss of the cuticle occurs, along with nail
  dystrophy and onycholysis with discoloration
  around the lateral nailfold
• A greenish color with hypo-
• nychial fluid accumulation
• may occur that results
• entirely from Candida,
• and not Pseudomonas infection

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Chronic Mucocutaneous Candidiasis

• CMC is associated with a defect in cell-mediated
  immunity
• The alterations include decreased IL 2 and
  interferon-gamma levels increased IL 10
• Usually manifests in infancy or early childhood
  (60-80 of cases)

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Clinically

• Infants often present with recalcitrant thrush,
  candidal diaper dermatitis, or both
• More extensive scaling of skin lesions and
  thickened nails and red, swollen periungual
  tissues can follow these infections
• Oral involvement may extend to the esophagus, but
  further extension is extremely uncommon

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• Nails may be markedly thickened, fragmented, and
  discolored, with significant edema and erythema
  of the surrounding periungual tissue, simulating
  clubbing

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• Skin lesions more frequently are acral and
  characterized by erythematous, hyperkeratotic,
  serpiginous plaques
• The scalp may be involved with similar
  hyperkeratotic plaques,
• which can result in
• scarring alopecia

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• Tinea Nigra

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Etiology

• It is due to infection by the fungus, P werneckii
• Occurs as a result of
• inoculation from a
• contamination
• source such as soil,
• sewage, wood, or
• compost subsequent
• to trauma in the
• affected area

Note the 2 celled yeast forms
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• Tends to occur in areas with an increased
  concentration of eccrine sweat glands
• Hyperhidrosis appears to be a risk factor for
  this disease
• Typically, the incubation period is 2-7 weeks
• A pigmentary change in the skin results from the
  accumulation of a melanin-like substance in the
  fungus

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Clinically

• Asymptomatic brown-to-black macule ranging from
  light brown to black discoloration, resembling
  silver nitrate or India ink stains
• The borders are typically discrete
• The surface may appear mottled or velvety
• The lesions are
• typically solitary,
• although may be
• multiple
• Located on the
• palms and soles

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• The shape of the lesion varies, and they may
  appear ovoid, round, or irregular
• The lesion slowly grows over weeks to months
• The size may range
• from a few
• millimeters to
• several centi-
• meters in
• diameter, depending
• on the duration

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• Piedra
• Etymology Sp.Stone

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Etiology

• White piedra is caused by the genus Trichosporon
  Behrend which consists of 6 human pathogenic
  species
• Black piedra is caused by the fungus Piedraia
  hortae
• Present in the soil, air,
• water, vegetables,
• or sputum

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Clinically

• Black piedra
• Consists of darkly pigmented, firmly attached
  nodules that vary in size to as large as a few
• millimeters in
• diameter
• The nodules feel
• hard

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• The most commonly affected area of the body is
  the scalp hair. Black piedra less frequently
  affects beards, mustaches, and the pubic hair
• The fungus grows into the hair shaft ultimately,
  it may cause hair breakage because of structural
  instability

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White piedra

• Consists of lightly pigmented, loosely attached
  nodules or gelatinous sheaths that have a soft
  texture
• The most commonly affected areas of the body are
• beards, pubic
• axillary hair,
• mustaches and
• eyelashes and
• eyebrows

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• Hair breakage occurs in both forms
• In both varieties of piedra, the surrounding skin
  is healthy