Download MBBS Dermatology PPT 9 Fungal Viral Infections Problem Based Learning Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Dermatology PPT 9 Fungal Viral Infections Problem Based Learning Lecture Notes

Fungal and viral infections-

Problem based learning

VERRUCA VULGARIS


? Describe the lesions

? Multiple circumscribed

verrucous papules on the thumb

? Surface shows black dots

? Diagnosis:
? Verruca vulgaris

? blackish discoloration-
? Capillary thrombosis
? Wart resolves with no sequalae


? ??

? Subungual verruca

? Causative agent?

plantar warts

Filiform warts


PALMAR WARTS

VERRUCA PLANA


? ??

? Pseudokoebnerisation- Lesions

may be arranged linearly

(pseudo Koebner's

phenomenon) due to auto-

inoculation.

Verruca plana

Verruca plana over a tattoo


? Epidermodysplasia verruciformis

Rare inherited disorder,

characterized by defective cell-

mediated immunity to certain

types of HPV (3, 5, 8, 9) resulting

in wide spread lesions.

? Plane wart-like lesion
? Pityriasis versicolor-like irregular,

scaly macules

? Anogenital warts
? Sexually transmitted disease.


? A variety of clinical variants, e.g.,

condyloma acuminata, papular

warts, and Bowenoid papulosis.
? Most frequently on the glans,

perianal region, vulva, and

cervix.

? Differential.....

? Condyloma lata

? Secondary syphilis


? Diagnosis
? Characteristic warty appearance

with a rough, dry stippled

surface.

? Presence of pseudo Koebner's

phenomenon, especially in plane

warts.

? Typical histology


? Treatment

? More than 50% of warts resolve

spontaneously

? Cryotherapy

? Cryogens: Liquid nitrogen, carbon

dioxide, and nitrous oxide.

Technique: A cotton-tipped

applicator dipped in cryogen is

applied firmly to the wart til a

smal halo of freezing appears on

adjoining normal skin. Or can be

sprayed using a cryocan.


? Electric cautery and

? Wart paint: Contains salicylic

radiofrequency ablation (RFA)

acid (a keratolytic agent) and

lactic acid in a quick drying

collodion or acrylate base.

? Topical agents
? Salicylic acid (10?25%)

? Retinoic acid (0.05?0.1%):

MOLLUSCUM CONTAGIOSUM


MOLLUSCUM CONTAGIOSUM

? Diagnosis of MC is based on:
? Presence of pearly white

umbilicated papules.

? Extrusion of the cheesy core

through the central crater;

characteristic cytological

appearance of the expressed

material.


? Pseudoisomorphic phenomenon

? Course -Self-limiting.

? Anogenital region: what should you ? Except in immunosuppressed and

suspect

atopics

? Sexual y transmitted MC

? In adult patients with extensive and

persistent lesions------- what should

you suspect?

? underlying HIV infection should be

ruled out.


CHICKEN POX

CHICKEN POX
? Morphology:
? Crops of papules with erythematous halo; r
? apidly become vesicular (dew drops on rose petal appearance), then

pustular.

? Eruption at different stages present.
? Heal with minimal scarring unless complicated by secondary infection

or hemorrhagic lesions (as seen in immunocompromised).

? Adults usually have a more severe eruption.

? Site: Centripetal distribution.

? Treatment: Specific antiviral therapy (acyclovir 800 mg, five times

daily ? 7?10 days) in adults and in immunocompromised individuals.

? None needed in children.


? ??

? Herpes Zoster
? Causative agent?
? Varicella-zoster virus

? Morphology??

? Very painful, segmental eruption of grouped papules and vesicles on an

erythematous, slightly edematous base

? Predisposing factors for reactivation are:

? Old age.

? Lymphoreticular malignancies, e.g., Hodgkin's disease and leukemia.

? Human immunodeficiency virus infection.

? Sometimes without apparent cause.
? Sites:

? Thoracic intercostal nerves,

? ophthalmic division of trigeminal nerve.

? Complications ??

? Postherpetic neuralgia

? corneal ulcers and scarring------- Eye involvement is indicated when

vesicles are present on the side of the nose (Hutchison's sign).

? Secondary bacterial infection

? Generalized ----in immunocompromised individuals and in those with

internal malignancies.

? Investigations
? giant cells on cytopathology is confirmatory.

? if disseminated hemorrhagic lesions present----????

? Rule out an underlying immunodeficiency (lymphoreticular

malignancies and HIV infection)
? Treatment:
? Self-limiting.
? Symptomatic treatment with analgesics.
? Specific treatment with antivirals (acyclovir, famciclovir, and

valacyclovir) in: (a) ophthalmic zoster (b) immunocompromised (c)

severe zoster (hemorrhagic lesions), and (d) elderly (to reduce

postherpetic neuralgia).

? Acyclovir: 800 mg, five times a day ? 7 days (adult dose).

? Famciclovir: 500 mg, three times a day ? 7 days.

? Valacyclovir: 1 g, three times a day ? 7 days


HERPES LABIALIS

? ??

? grouped vesicular lesions


? ??

? erosions with polycyclic margins.

? erosions with polycyclic margins.

? Cause?

? HSV

? Why difference in severity?

? Primary infection, more severe and

associated with constitutional

symptoms.

? Recurrent infection manifests as

grouped papulovesicular lesions which

rupture to form polycyclic erosions.
? HSV (type I and type II).
? Type I generally causes lesions above the waist,
? while type II causes genital infection.
? After primary infection (first infection), the virus lies dormant in

sensory ganglion and

? gets activated from time to time.

? ?? Transmission
? Direct contact: Usually occurs in children from an infected adult who

is often asymptomatic yet shedding virus.

? Sexual contact: Usually in adults, herpes genitalis being the most

common cause of infective genital ulcer disease. Again asymptomatic

shedding important.


? ??

? Primary HSV infection

? may present as acute

gingivostomatitis: characterized by

closely grouped vesicles which

rapidly form polycyclic ulcers

covered with a yel ow

pseudomembrane. Heal in about a

fortnight

? Malaise, fever, and

lymphadenopathy are frequent.

? ??
? Primary herpetic genital

infection


? Bed side test that u would do ????

? Tzanck smear -
? multinucleated giant cells

Tzanck smear, showing multinucleated giant

cel s


? Serology:
? Antibody titers rise with primary infection (IgM initially, IgG later).
? Though IgM levels fall, IgG levels persist.
? Are of doubtful diagnostic significance in recurrent infections but
? help in primary infection.


? Morphology??
? painful oblong vesicles on hands
? erosions in oral mucosa

? Hand, Foot, and Mouth Disease

? Treatment: Symptomatic.


FUNGAL INFECTIONS

? ??

? ANNULAR PLAQUES
? relative clearing in the center.
? edge of the lesion showing

papulovesiculation and scaling.

? TINEA

T. CORPORIS


T. CAPITIS


T.CAPITIS

? Noninflammatory tinea capitis:

? Caused by anthropophilic organisms (e.g., T. verrucosum), so less

inflammation.

? Inflammatory tinea capitis (kerion)

? Caused by zoophilic dermatophytes (e.g., M. canis), which elicit

intense inflammation.

? boggy swelling with pustulation. Often, the pus discharges from

multiple orifices. Hair from such a swelling is easily and painlessly

pluckable


? WHICH BEDSIDE TEST WOULD

YOU DO??

? Potassium hydroxide (KOH)

scraping AND MOUNTING


? Technique

? Mount specimen on glass slide,

adding 10% KOH (to dissolve the

keratin).

? Keep for half an hour;

? nail clippings require longer (2 h)

and warming (not boiling).

? Fungus is easily detected using the

low power objective lens (10 ?)

with the iris diaphragm closed and

the condenser positioned down.

? Scenario: tinea capitis outbreak

in a school

? What investigation should you

do?

? Wood's light examination- green

fluorescence


? General measures
? Keeping area dry.
? Avoiding use of synthetic

clothes.

? In recurrent infection,

prophylactic use of anti-fungal

talc

? Systemic therapy is

recommended in the following

situations:

? Extensive dermatophytic

infections.

? Tinea unguium.
? Tinea capitis


P. VERSICOLOR

? Perifollicular, hypopigmented (or ? KOH mount

hyperpigmented), macules

surmounted with branny scales. ? shows characteristic `spaghetti

and meat ball' appearance.

? Upper trunk, neck, upper arms.
? Topical agents

? Systemic agents

? Imidazoles:Ketoconazole, 2%

? Needed in extensive lesions or

applied daily for 4 weeks.

when recurrences are frequent:

? Selenium sulfide: 2.5% lotion in a ? Ketoconazole, 200 mg daily for

detergent base, used weekly for

three consecutive days.

4 weeks.

? Fluconazole, 400 mg single dose.
? Itraconazole, 200 mg daily for 7

days.

CANDIDAL INTERTRIGO


Candidal paronychia

Candidal balanoposthitis

? frayed lesion in the groin with

satellite pustules.


? Oral candidiasis:

? KOH mount shows budding yeasts

and pseudo- hyphae.

? Culture

? Rule out diabetes in patients with

recurrent infection.

? Rule out immunocompromised

states in

recurrent/extensive/atypical

disease.

? General measures

? Topical agents

? Predisposing factors should be

? Candidal intertrigo:Topical azoles

sought and eliminated.

(clotrimazole, miconazole, and

? Intertriginous areas should be kept

ketoconazole) are effective.

dry by adequate wiping after a

? Candidal paronychia: Topical azole

bath.

lotions

? In paronychia, prolonged

? Oral candidiasis: Lotions and oral

immersion in water is best avoided.

suspensions of azoles. Or nystatin.

? Genital candidiasis : Imidazole

pessaries for vaginal infection.

Topical azoles for balanoposthitis.


? Systemic therapy recommended ? Recurrent oral candidiasis: In

in the following situations:

immunocompromised patients

? Candidal vulvovaginitis: Single

(e.g., HIV infection), fluconazole,

dose fluconazole (150 mg) or

150 mg weekly dose.

itraconazole (400 mg).

? Chronic mucocutaneous

? Weekly doses of fluconazole

candidiasis: Requires prolonged

(150 mg) for recurrent problem.

therapy

MYCETOMA


MYCETOMA

? Begin as subcutaneous nodules,

? which slowly evolve into abscesses and draining sinuses

? Over period of time, the surrounding tissue becomes hard due to

fibrosis.
? Investigations
? Establish the diagnosis of mycetoma.
? Identify the causative organism ( actinomycetes vs eumycetes).
? Find the extent of local spread

? Examination of pus and granules
? Histology
? Culture
? X-ray of the affected part


? Treatment depends on whether

? Eumycetoma

the mycetoma is actinomycotic or

eumycotic.

? Ketoconazole

? Actinomycetoma Responds to a 6? ? Itraconazole.

9 months course of combination of ? Amphotericin B in resistant cases

chemotherapeutic agents like:

Streptomycin + dapsone or co-

trimoxazole.

? Surgical intervention:

? Co-trimoxazole + amikacin.

? Deep debridement and even

? Tetracyclines + streptomycin +

amputation may need to be done

rifampicin.

in case of recalcitrant lesions

? Penicil ins + gentamycin + co-

trimoxazole

? ulcerated nodules are arranged

in a linear fashion along the

lymphatic drainage.

? single infiltrated plaque


? Sporotrichosis

? Treatment:

? Causative agent-

? Saturated solution of potassium

? Sporothrix schenckii.

iodide. Or itraconazole.

? cauliflower-like hypertrophic

plaque

? Characteristically, surface is

studded with black dots


? Chromoblastomycosis

? Trauma prone sites.
? Treatment:

? Several fungi can cause

? Itraconazole, flucytosin

chromoblastomycosis

? painless subcutaneous swelling

with smooth edge which can be

raised by inserting a finger under

it

? Subcutaneous phycomycosis

? Potassium iodide
? GOOD DAY !!!!