CUTANEOUS INFECTIONS AND INFESTATIONS

DR. MOHAMMED ALSHAHWAN MD

OBJECTIVES 1. General understanding of the causative

organisms of common skin infection(CSI).

2. Focus on CSI clinical presentation.

3. Overview of the basic investigations done and general knowledge of first line therapy.

BACTERIA (impetigo , erysipelas &cellulits )

VIRUS (wart ,herpes simplex & herpes zoster)

FUNGUS (Tinea , candidasis)

PARASITE (Lieshmaniasis ,scabies & pediculosis)

BACTERIAL I. Impetigo Superficial non-follicular infection due to

staphylococcus and streptococcus Children not sick pustule (honey-colored crust ) Face and Acral areas Primary or secondary

II. Erysipelas deep cutaneous infection (Dermal) due to streptococcus after penetrating trauma (

CHRONIC LYMPHEDEMA) sick Face and Acral areas Unilateral sharply demarcated edematous red

plaque

III. Cellulitis deep cutaneous infection (up to SC FAT) due to streptococcus after penetrating trauma (

CHRONIC LYMPHEDEMA) sick Face and Acral areas Unilateral Diffuse (NOT well demarcated)

edematous red plaque Blood Culture in immuocompramized pts.

VIRAL INFECTIONWART Human papilloma virus (HPV) Direct contact Asymptomatic transmition Delay in presentation Oncogenic potential (HPV 16 and 18) High recurrence rate

CUTANOUS ( HPV 1 and 3 )

common wart

flat wart

planter wart

GENITAL (HPV 6 and 11)

classic

condyloma acuminata

GENITAL WART

*STD

*Oncogenic HPVs ( Cervical cancer)

*Usually more persistent and difficult to treat .

TREATMENT* Tissue destructive modalities Keratolytic (salicylic acid and podophyllin) Cryotherapy ( Liquid nitrogen) Electrotherapy CO2 laser

* Immunotherapy

HERPES SIMPLEX

Human Herpes virus I and II

Direct contact

Asymptomatic transmition

Latency

High recurrence rate

CUTANEOUS ( HSV I ) orolibialis Initial Herpatic whitlow Recurrence herpes ophtalmicus

GENITAL ( HSV II )

Initial Recurrence

Incubation period : 7- 10 days. After 24-48 hours of burning and tingling sensation the patient develop grouped vesicles on erythematous base which ulcerate within 24 hours.

The whole illness is around 7-10 days.

Tzank smear

Direct fluorescent antibody test

Viral culture

Blood serology

VARICELLAE ZOSTER VIRUS (VZV)

RESPIRATORY DROPLETS CHICKENPOX ( Children)

HERPES ZOSTER (Adult) is due to reactivation of VZV which was dorminant in nerve root ganglion

CHICKENPOXIncubation period : 2 weeksProdrom of respiratory coryza followed

by disseminated red macules with central vesicles.

The whole illness : 3 weeks The patient contagious 5 days before

and 5 days after skin eruption

HERPES ZOSTERAfter 24-48 hours of burning and tingling

sensation the patient develop grouped vesicles on erythematous base which ulcerate within 24 hours.

The whole illness is around 7-10 days.

Post-herpetic neuralgia (PHN) which usually persist for around 4 weeks.

It is almost always DERMATOMAL

SPINAL (Thoracic )

CRANIAL ( Trigeminal)

SERIOUS involvement1.Ophthalmic division of trigeminal nerve.

2. Geniculate ganglia (Ramsey-hunt syndrome)

3.Sacral ganglia.

TreatmentHERPES SIMPLEX Acyclovir 200 mg five time a day for a

weekHERPES ZOSTERAcyclovir 800 mg five time a day for a

week

FUNGALDERMATOPHYTE

Tinea Pedis (most common)

1.Erosive interdigitalis

2. Hyperkeratotic type(T. rubrum)

3. Inflammatory type(T.mentagrophyte)

Tinea corporis / Tinea cruris1.Hyperkeratotic type (T. rubrum) well-demarcated annular red

hyperkeratotic plaque with central clearing (Ring worm)

2.Inflammatory type (T.mentagrophyte) well-demarcated edematous red

plaque with superimposed pustules

Tinea Capitis1.Hyperkeratotic (black dot) usually due to T. tonsurans 2. Inflammatory (Kerion) usually due to M. canis complex3. Favus * Due to T. schoenleinii * it characterized by the presence of

Scutulae .

YEASTCandidosisDue to candida albicansIt is a commensal flora of the gut

which become pathogenic when the immune status of the person changed

physiological (old age , neonate and pregnancy)

pathological ( DM, HIV and organ transplant)

Itrogenic (long course of Antibiotics)

MUCOSAL

1. Oral

oral thrush

angular chilitis

2. Genital

valvuvaginitis

CUTANEOUS

it favor wet areas

Candidal intertrigo ( Napkin rash)

peripherally spreading glazed red patch with scaly border and satellite pustules

Candidal paronychia

pityriasis versicolor

Due to Malassezia furfur

Asypmtomatic

Well-demarcated brown patches with branny over the trunk and upper extremities

1. Scraping,Clipping and Hair blucking

KOH/microscopy Culture

2. Skin biopsy Histopathology with PAS stain

Culture

Topical Antifungal Nystatin preparation (oral thrush) Imidazoles e.g. cotrimazole and miconazoleSystemic Antifungal Imidazoles e.g. Itraconazole and fluconazole Allylamine e.g. Terbinafine Griseovulvin

PROTOZOA

Lieshmaniasis

Protozoa called Lieshmania

Sand fly (premastigote)

Macrophage (Amastigote)

Lieshman-Donovan bodies

Localized Cutaneous Well-demarcated ulcerated nodule over the exposed areas after a trip to an endemic area ( H/o of insect bite)

Disseminated Cutaneous Mucocutaneous Visceral

Skin biopsy

Histopathology with Gimsa stain

Lieshman-Donovan bodies

Culture

PCR for DNA

Liesmanin test

Resolve spontaneously leaving a scar

Antimony (Pentostam) either Intralesional or Intramuscular to shrink the lesion

Scabies Mite called sarcoptes scabei which residue in burrows in the

stratum corneum laying eggs then dieing and the eggs will maturate in 2 weeks period and the cycle repeated.

Skin lesions are Secondary eczematous eruption due to immune reaction to the mite and eggs

When to suspect scabies ?

1.pruritus mainly at night

2. Other member of the family also having severe pruritus

3. Pruritus and skin eruption is more severe in the flexors

Document See the mite or eggs

Permethrin cream

Lindane cream

Malathion lotion

2.5% sulphur ointment

PEDICULOSIS

Head lice (Pediculosis Capitis)

Children

Body lice (Pediculosis Corporis)

Homeless people and vagrants

Pubic lice (Pediculosis Pubis)

STD ( partner should be treated)

The diagnosis can be conformed by seeing the lice eggs ( NITs)

Best treatment is SHAVING for head and pubic lice. Alternatives:

Permethrin creame rinse

Malathion lotion

THANK YOU