Cutaneous Manifestations of AIDS 2

8/3/2019 Cutaneous Manifestations of AIDS 2

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Cutaneous infections and

AIDSThe pathogens involved and

their detection


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Pathogens involved:

VirusesFungi

Bacteria

Parasites

Arthropod


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HIV/AIDS

mucocutaneous

infections

H.Schoefer

1998 (%)

N=330

Kumarasamy

2000 (%)

N=833

Oral Hairy leukoplakia 45.0 2.3

Oral Candidiasis 15.8 (Candidiasis 45.0

Seborrheic dermatitis 40.3 ----------Dermatophytes 30.6 8.0

Staph infections 30.3 (folliculitis) 2.9

Herpes genitalis 25.8 7.7

Herpes Zoster 21.2 11.2

Pyoderma 18.2 ---------

Molluscum contagiosum 1.3 26.0

Scabies --------------- 0.5


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Viruses

Herpes Zoster infection - HZV

Herpes labialis, anogenital Herpes - HSV

Molluscum contagiosum - Pox virus (DNA)

Warts - HPV


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Clinical appearance:

Molluscum contagiosum

Warts

Diagnosis


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HSV or HZV Lab diagnosis;

Viral culture most sensitive clinicalmethod Culture sensitivity is higher when the herpetic

vesicular lesions first appear and before they ulcerateLater ulcerative lesions may have no detectable virus.

Antigen detection less sensitive.

Serologic testing (antibodies)for detection

of past infection not acute infection, Immunocompromised patients unlikely to mount

a significant (fourfold or greater) rise in anti-HSVtitre between acute and convalescent samples.


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Viruses typically appear as geometric arrays of

spherical particles

Herpes viruses - electron micrograph


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Bacteria:

Staphylococcus infections

Folliculitis

Boils (Furuniculosis)

Pyoderma


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Diagnosis of Staphylococcus aureusinfections

Specimen - swab in transport medium

Gram stain - Gram positive cocci

Culture Sheeps blood agar

Identification: Gram + coagulase test +DNase


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Scabies: Sarcoptes scabeiDiagnosis:Look for - presence of burrows or rash

at site of infection- mites, eggs, mite faecal matterin Skin scraping

Parasite

Egg

Mite


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Superficial Fungal infections

Dermatophyte infectionsCandidiasis

?Seborrheic dermatitis

Superficial manifestations of systemic infection:

Histoplasmosis

Cryptococcosis


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Candida infections appropriate specimen

Onychomycosis

Specimen:

Scraping or

Clipping

Interdigital

CandidiasisSpecimen:Scraping

OralCandidiasis

Specimen:

Swab


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Lab Diagnosis of Candidiasis

MicroscopySwab

Smear

Gramstain/PAS

Pseudohyphae+blastospores

Skin scrape10% KOH

Preparation

Candida species


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Lab Diagnosis of Candidiasis

Culture on Sabouraud dextrose agar+chloramphenicol. Incubate at 37C

Gram stain, germ tube test,chlamdospore production,

Carbohydrate assimilation


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Lab Diagnosis of Dermatophyte infections

Tinea pedis

Tineacorporis Tinea unguium

Tinea capitis


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Specimen Clippings or scrapings

Nail scrapings and clippings on black paper


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Microscopy:

10or 30% KOH preparation

Hair invasion

Ectothrix

Endothrix

Fungal hyphae+ arthrospores

Skin


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Culture on Sabouraud dextrose agar+ chloramphenicol+cycloheximide Incubate at 25C

Trichophytonrubrum


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Cryptococcosis

Cryptococcus neoformans (Filobasidiellaneoformans)

Varieties Serotypes Main geographic

distributionneoformans D Northern Europe

gattii B,C* Tropical + sub tropical

grubii A* World-wide

Source: pigeon droppings (A,D), gum trees (B,C)


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Cryptococcus neoformans in india inkpreparation shows importantidentification features

Carbohydratecapsule

Cell wall

Cell contents


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AIDS associated cryptococcal infection May present with severe progressive

pneumonia + acute dyspnoea

Disseminated cutaneous lesions pustular + papular, nodular, ulceratedlesions

Meningitis


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Specimens to diagnose cryptococcal

infectionSputum

Bronchoalveolar lavage

Transbronchial biopsyBlood culture

BiopsyUrine C. neoformans is aClass 2 Pathogen


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Detection methods Microscopy 10%KOH + india ink preparations

Culture Chocolate agarSabouraud dextrose agar

chloramphenicol

Niger seed agar

Serology to detect Ab and capsular antigen


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Cryptococcus neoformans in india ink


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Culture characteristics


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Latex particle agglutination test Latex particles coated with Ab to carbohydrate capsule Agglutinates in presence of Antibody Specimens:

Serum, CSF, urine, BAL, aspirate

Sensitivity 75-100% Specificity 90-100%

False positives:Rheumatoid factor

KlebsiellaSyneresis fluidSome soaps, disinfectants


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India ink

Culture + antigen test Culture

+

+ve

+ve

- ve

Summary C.neoformans lab diagnosis


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Histoplasmosis

Histoplasma capsulatum (Ajellomyces capsulatus)

Dimorphic fungus

37C 25C

Yeast phase Filamentous phase+Infection Macroconidia

Microconidia


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Histoplasma capsulatum


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Clinical Features1. Primary lung infection

Sub-acute/acute (caves disease)

Flu-like illness usually self-limiting

Acute pneumonia2. Chronic cavities

3. Disseminated from lung RES Wt. LossFever

Liver,spleenUlcers mouthSkin lesions

Severe acute pneumonia


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Specimens

Sputum BAL

Lymph nodes Liver biopsy

Blood Bone marrow Urine

Biopsy from skin lesions

H.capsulatum is aClass 3 pathogen


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Tests available

Microscopy

Culture

SerologyPCR


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H.capsulatum - PAS stain

Smallintracellularyeast cells


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H. capsulatum

Cultures


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H. capsulatum

Yeast phase - 37C


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H.capsulatum

Macro and micro-conidia - 25C


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Comparison of sensitivities of different diagnostictest for disseminated histoplasmosis in patients

with AIDS

J.Wheat Clin.Microbiol Rev 1995


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Diagnostic tests are available in Zimbabwe?

Microscopy Gram. India ink, KOHCultureCryptococcal antigen test

Cutaneous Manifestations of AIDS 2

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