|
Dermpath-India Site created by Dr Sampurna Roy MD
|
Candidosis (Candidiasis)
|
| Created by Dr Sampurna Roy: |
PUB MED: ARTICLES RELATED TO CANDIDOSIS |
|
Granulomatous Reaction Pattern of the Skin
Annular Elastolytic Giant Cell Granuloma Skin lesion in Crohn's Disease Interstitial Granulomatous Dermatitis |
|
Pulmonary Infection Histoplasmosis (Histoplasma Capsulat um)Respiratory syncytial virus infection |
Candida albicans is the most common fungal pathogens of mankind.
These are normal inhabitants of oral cavity, GI tract, & vagina. Fungi are yeast-like cell with pseudohyphae & hyphae.
Predisposing factors:
i) Prolonged antibiotic or steroid therapy.
ii) Diabetes mellitus, advanced malignancy, pregnancy, oral contraceptives etc
iii) Burns, surgery, urinary tract catheters & GI tract ulcers etc.
iv) Frequent exposure of body or hands or feet to water.
Site:
Most common site is superficial mucosal surface of oral cavity (thrush). Other sites include vagina , folds of skin and nail (middle finger is frequently involved)
Oral thrush:
Creamy-white, friable, patches composed of organisms & inflammatory debris, forms pseudomembrane. It covers tongue, soft palate & buccal mucosa. When detached, it leaves red, inflamed surface . In severe cases, there is ulceration.
Vulvovaginal:
Pseudomembrane extends to perineum & develops in pregnancy or after oral contraceptives.
Skin:
Acute Superficial candidosis is the usual form of lesion.
Chronic mucocutaneous candidosis is characterized by chronic and persistent infection of the mucous membrane by species of Candida. Chronic lesions are seen in persons with immune defect.
Paronychia & onychomycosis may occur.
Location: Folds of skin in axilla, groin, inframammary area, intergluteal folds, interdigital spaces & umbilicus.
Gross: It shows pruritic eczematous area with vesicles or pustules in the margin.
“Candida granuloma” - this is a disfiguring cutaneous lesion and appears as warty, hyperkeratotic, papules or plaques.
Acute: i)Neutrophils in the stratum corneum is the characteristic feature.e ii) Diffuse inflammatory infiltrates & intraepithelial microabscesses. iii) Fungal elements are sparse and demonstrated with the PAS stain.
Silver methenamine stain (Grocott's method) : Stains fungal hyphae black against green backround. It is more reliable than PAS for detecting degenerate fungal organisms.
Chronic: i) Marked hyperkeratosis & pseudoepitheliomatous hyperplasia. ii) Compact orthokeratosis &scale crust formation iii )Spores and hyphae are easily identified even without PAS stains. iv) Granulomatous dermatitis : ill-defined granulomas composed of lymphocytes, plasma cells, epithelioid cells and occasionally giant cells.
Disseminated /Systemic Candidiasis:
Gastrointestinal tract: Mostly esophagus & stomach. Lesions consist of punctate mucosal erosion or ulcer covered by pseudomembrane. Organisms invade submucosa & submucosal blood vessels.
Urinary tract: Causes cystitis & ascending pyelonephritis, often papillary necrosis of kidney ; Necrotic material with fungi, forms “fungal balls” causing ureteric obstruction & hydronephrosis ; Bilateral miliary necrosis may be seen in hematogenous dissemination.
CNS: This is the most common fungal infection in CNS. It causes multiple microabscesses with non-caseating granulomas and localized meningitis.
Lungs: i) By inhalation produce bronchopneumonia ; ii) By hematogenous spread cause bilateral hemorrhagic nodules.
Laboratory diagnosis: ( Read :Histopathological Patterns in Cutaneous Infection ) Immunofluorescence & immunohistochemistry.
Pathology and clinical correlates in oral candidiasis and its variants: a review.Oral Dis. 2000 Mar;6(2):85-91.Although Candida albicans is well recognised as the major agent of oral candidiasis, it is not clear why several variants such as pseudomembranous (PC), erythematous (EC) and hyperplastic candidiasis (HC) manifest in different individuals, sometimes singly and on other occasions, in combination. The present review focuses on recent histopathologic and immunocytochemical studies as well as the pathogenic attributes of the yeast, in an attempt to address the following queries. (1) Do histopathologic studies of the different variants of candidiasis in immunocompetent and immunocompromised individuals help explain these varying manifestations? (2) Under what circumstances does oral candidiasis manifest as a pseudomembranous rather than an erythematous lesion or vice versa? (3) Are there differences in immunoreactivity in closely adjacent mucosae so that the variable presentation of such lesions reflect differences in the local mucosal immune system? Recent studies of PC, EC and HC offer some insights into the pathogenic mechanisms involved. Histopathologic and immunohistochemical finding in cases of PC and EC in HIV-infected patients and controls appear to be comparable, with a marked reduction or even an absence of CD4+ cells. The latter phenomenon is marked in PC compared with the EC, and explicable in terms of a breakdown of the local immune response in the former, and a hypersensitivity reaction against Candida antigens in the latter. Hyperplastic candidiasis on the other hand could be considered a superficial cellular reaction against the pathogen, which cannot entirely be eradicated by the systemic or local host immune response. The virulent attributes of the fungus, such as the production of extracellular proteinases, do significantly differ within and between species and thereby play a contributory role in the genesis of the clinical variants. Although the available data do give a tantalising glimpse of the contributory mechanisms for the aetiopathology of PC, EC and HC, further research is warranted to elucidate response of the host to this ubiquitous fungal pathogen. |
CLICK ON THE IMAGES
PAS stain
Grocott's silver stain
|
Cutaneous infection and infestations Histopathological patterns in cutaneous infections : Bacterial, Rickettsial and Chlamydial infection |
|
Gross examination of the skin specimen |