[11] Fungal diseases

Tinea versicolor

• Mild, chronic scaling,and hypo-or hyperpigmentation of skin; face, trunk, and limbs

• may take on a mottled appearance

Tinea versicolor

Most pronounced in young people who are frequently exposed to the sun, because the area affected does not tan well.

folliculitis, psoriasis and seborrheic dermatitis

Other superficial skin conditions in which Malassezia is implicated

• Topical or oral antifungals

• Selenium sulfide

• Zinc pyrithione

Tx for Tinea Versicolor

Ringworm

Also known as “tinea” or “dermatophytosis”

Ringworm

Causes an itchy, red, circular rash – like

a “ring-shaped worm” under the skin

Ringworm

Signs and sx:

• Depending on the location (e.g., various skin lesions, loss of hair, crumbling of nails)

Tinea capitis

• Ringworm of the scalp

• Common among children resulting in scaly,

  red, itchy bald spots or patches on the scalp

  and loss of hair

• Direct contact; contact with fomites

Tinea cruris

• Ringworm of the groin, inner or upper

  thighs, or buttocks

• “Jock itch”

Tinea pedis

Ringworm of the feet

• “Athlete’sfoot”
• Requires warmth and moisture

Tinea pedis

most prevalent tinea type

Tinea unguium

Ringworm of toenails or fingernails

Tinea unguium

aka Onychomycosis

Clotrimazole, Miconazole, Griseofulvin,
Terbinafine

Tx for tinea

Candidiasis

Signs and sx:

Infected skin is colored bright red and may be inflamed; Thrush in mouth (whitish plaques on tongue)

Clotrimazole, Miconazole, Fluconazole, Nystatin

Tx for candidiasis

Candida albicans

Causes infections of mucous

membranes and is a common cause of oral thrush (in oral mucosa), diaper rash (groin), and vaginitis

• Opportunistic pathogen that may proliferate when the normal bacterial microbiota are suppressed

Sporotrichosis

Signs and sx:

Pustule or ulcer on hands often with nodules on arms; may spread to nearby lymphatic vessels

(Oral) Potassium Iodide Solution

Tx for sporotrichosis

Sporotrichosis

• Results from a soil fungus that penetrates the skin through a wound

• Forms a small ulcer on the hands, then enters the lymphatic system

• Fungi grow and produce subcutaneous

  nodules along the lymphatic vessels

Sporotrichosis

• Commonly occurs among gardeners or

  other people working with soil and plants

• Especially those who prune roses, because

  they may be stuck by a rose thorn.

Fungal meningitis

• Cryptococcus neoformans causes _____ in immunosuppressed patients

• The escape of the yeasts into the blood is intensified by weakened host defenses and results in severe complication

Cryptococcosis

Signs and sx:

Headache, nausea, stiff neck, mental changes, coma, paralysis, eye disturbances, seizures

Cryptococcus neoformans

shows an extreme affinity for the meninges and brain forming tumor-like masses causing CNS signs and symptoms

Transcellular penetration

ability of C. neoformans to penetrate the Blood-brain Barrier

WBC > 500; Elevated protein (> 60 mg/dL)

Lab values that help diagnose fungal meningitis

Amphotericin B, Flucytosine, Fluconazole

Tx for cryptococcosis

Coccidiodomycosis

Signs and sx:

Begins with pulmonary infection (focal pneumonia) → Meningitis (more severe manifestation), osteomyelitis, and skin granulomas

Spherule

C. immitis, On special media incubated at 37°C to 40°C, an arthrospore germinates into the parasitic phase, a small, spherical cell called a _____ that can be found in infected tissues as well

Spherule

This structure swells into a giant sporangium that cleaves internally to form numerous endospores that look like bacterial endospores but lack their resistance traits

barrel-shaped arthrospores

Mold phase mycelium of C. immitis fragments into _____

Coccidiodomycosis

Inhalation of arthrospores (certain groups have a genetic susceptibility, causing more serious disease)spherules in the lungsreleasing spores into the lungsto other organs (in people who have defect in cell-mediated immunity)

Amphotericin B, Fluconazole or Itraconazole

Tx for coccidiodomycosis

Aspergillosis

Signs and sx:

Usually non-specific, and mimic broncho-pneumonia; May also present with chest pain and haemoptysis

Aspergillosis

Exogenous sources → enter through respiratory portals → adherence to epithelial surface layers → further dissemination

to different host sites

Aspergillosis

Inhalation of spores (decaying vegetation); compost piles; may also occur for those severely immunocompromised individuals

Corticosteroids or Disodium cromoglycate

Tx for aspergillosis (allergic forms)

Amphotericin B, Itraconazole, Surgery

Tx for aspergillosis (aspergilloma)

Rapid administration of Voriconazole or Amphotericin B

Tx for aspergillosis (invasive)

Coccidiodomycosis

Also known as “San Joaquin Valley fever”

Coccidiodomycosis

Signs and sx:

Fever, cough, chest pain, loss of appetite and weight; less frequent rash, pain in joints; skin, mucous membranes, brain and internal organs
Incubation period: 2 days to 3 weeks

Coccidiodomycosis

After lodging in lungs → arthrospores develop into spherules that mature and discharge their endospores, each of which can develop into another spherule

Histoplasmosis

• Usually benign but occasionally mimics tuberculosis

• Associated with bird and bat droppings

Histoplasmosis

Also known as “Ohio Valley fever”

Histoplasmosis

Signs and sx:

Mild respiratory symptoms; less frequent general malaise, weakness, fever, chest pain, cough; may result to cavity

lung lesions

Histoplasmosis

Inhalation of airborne spores from soil; grows in soil contaminated by bird or bat droppings (appropriate moisture and pH)

Histoplasmosis

Spores undergo metamorphosis to tissue phasegranuloma formation

(Incubation Period: 5-8 days)

Amphotericin B (IV), Itraconazole

Tx for histoplasmosis

Blastomycosis

• The rarest or the least common systemic fungal infection

• May occur in immunocompetent hosts

Blastomycosis

Signs and sx:

May be asymptomatic;
Pulmonary symptoms (cough, chest pain & dyspnea) may predominate; Chronic disseminated disease with fever, fatigue, weight loss, night sweats, lung involvement and skin ulcers

Blastomyces dermatitidis

May exist in warm, moist soil of wooded areas/terrain rich in organic debris; commonly found in outdoorsmen and hunters

Blastomycosis

Acquired through inhalation of spores → Widespread pyogranulomatous infection through hematogenous spread

involving the lungs, skin, bone, and genitourinary tract

Amphotericin B (IV), Itraconazole

Tx for blastomycosis

Pneumocystis pneumonia

Associated with AIDS patients, elderly people, premature infants, or patients that are severely debilitated or

malnourished

Pneumocystis pneumonia

Signs and sx:

Non-specific: cough, fever, shallow respiration, and cyanosis

Intact immune defenses; Deficient immune systems

Pneumocystis jirovecii is held in check by lung phagocytes and lymphocytes for people with _____. For people with ____, it multiplies; fungi adhere tenaciously to the lung pneumocytesinflammatory condition  lung epithelial cells slough off, and a foamy exudate builds up.

Suctioning of airways, Trimethoprim- Sulfamethoxazole (primary treatment), Pentamidine

Tx for Pneumocystis pneumonia

Candidiasis

Signs and sx:

For females: vaginal itching, burning sensation, presence of discharge; For males: urethritis

Candidiasis

Common in immunosuppressed individuals; also more common in sexually active women, possibly relating to changes in epithelium; but

not necessarily transmitted sexually

Candida albicans

Can exhibit the formation of pseudohyphae - in this form, it becomes resistant to phagocytosis

overgrows mucosal tissue

Since C. albicans is NOT affected by antibacterial drugs, it sometimes

________ when antibiotics suppress the normal bacterial

microbiota.