PP's derm

presentation: nodules, cysts, papules, pustules, open/closed comedones

etiology:

• sebum/androgen production

• abnormal keratinocyte desquamation

• C. acnes colonization of pilosebaceous unit

• inflammation

Bacillus anthracis

Edema toxin mimics cAMP

Lethal toxin → septic shock and death

RF: occupational exposure from direct contact w/ infected animals and carcasses

• i.e taxidermist

Cutaneous:

• painLESS papule → vesicle → black eschar ulcer (painless and necrotic) → bacteremia and death

Pulmonary:

• via inhalation of spores

• flu-like rapidly progresses to fever, pulm hemorrhage, mediastinitis, and shock

• Woolsorter’s disease

• CXR: widened mediastinum

Bartonella henselae or quintana

erythematous violaceous papules to nodules

RF: immunocompromised

Dx: Warthin-Starry silver stain

Clostridium botulinum

heat labile

MOA: inhibits ACh release from NMJ

adults ingestion preformed toxin

babes ingest spores → floppy baby syndrome, descending flaccid paralysis

si/x:

• diplopia

• dysarthria

• dysphagia

• dyspnea

Ehrlichia chaffeensis

vector: tick

fever, HA, malaise

maculopapular rash

leukopenia

thrombocytopenia

increased ALT/AST

monocyte w/ morulae B in cytoplasm

• mulberry like inclusion

Mycobacterium leprae

reservoir: armadillos

MC in India and Africa

“Hansen dz”

Lepromatous:

• diffusely over skin

• leonine facies

• communicable → high bacterial load

• low CMI

• Th2 response

Tuberculoid:

• few hypoesthetic hairless skin colored plaques

• high CMI

• Th1 response

• low bacterial load

Borrelia burgdorferi

transmission: ixodes deer tick

reservoir: mouse

MC in NE US

Stage 1: early localized, erythema migrans bullseye configuration, flu-like symptoms

Stage 2: early disseminated, carditis, AV block, Bell’s palsy, migratory myalgia, transient arthritis

Stage 3: late disseminated, encephalopathy, chronic arthritis

Rickettsia rickettsii

vector: tick

MC in South Atlantic, esp NC

rash starts at wrist and ankle → trunk, palm, sole

HA

fever

rash

MC in nares, ears, axilla, and groin

results in skin infx associated w/ hair follicles and carbuncles, organ abscesses, pneumonia (after influenza virus infx), endocarditis, septic arthritis, osteomyelitis

MRSA: serious nosocomial and community-acquired infx due to altered penicillin binding protein

fever

generalized erythematous rash

sloughing of upper layers of epidemis

(+) Nikolsky sign

MC in newborns and children, or adults w/ renal insufficiency

(-) blood culture

severe multisystem disease w/ cutaneous and internal involvement

menstrual: young women w/ superabsorbent tampons

nonmenstrual: nasal packing

fever

hypoTN

scarlatiniform eruption

palmoplantar desquamation

sharply defined fiery red plaque

superficial variant of cellulitis in upper-mid dermis

(-) culture

increased DNase B and ASO titer

MC: streptococcus pyogenes

GAS pharyngitis

fever

sore throat

blanching macular erythema

sandpaper like body rash

strawberry tongue

circumoral pallor

(+) erythrogenic toxin

(+) culture

elevated DNase B and ASO titer

painLESS chancre

dark field microscopy to visualize treponemes

(+) VDRL in 80%

copper colored maculopapular rash

condyloma lata: smooth painLESS wart like lesion on genitals

lymphadenopathy

patchy hair loss

confirm w/ dark field

VDRL/RPR and FTA-ABS

gumma (chronic granuloma)

aortitis (vasa vasorum destruction)

neurosyphilis (tabes dorsalis, general paresis)

argyll roberston pupil

broad based ataxia

(+) Romberg

Charcot joint

stroke w/o HTN

rhagades: linear scar at angle of mouth

snuffles w/ nasal discharge

saddle nose

notched Hutchinson teeth

mulberry molars

short maxilla

saber shins

CN8 deafness

treat mother in 1st trimester

Clostridium tetani

tetanospasmin block release of GABA and glycine from Renshaw cells

spastic paralysis

trismus lockjaw

risus sardonicus: raised eyebrows and open grin

opisthotonos: spasm of spinal extensors

Rickettisia typhi

vector: flea

fever

erythematous macules and papules

rash starts centrally and spreads out

sparing palms and soles

Rickettsia prowazekii

human body louse

fever

erythematous macules and papules

rash starts centrally and spreads out

sparing palms and soles

acute painFUL spreading infx of deeper dermis and SQ tissues

fever

MCC: S pyogenes or S aureus

RF: break in skin from trauma or another infx, immunosuppressed

unilateral

very superficial skin infx

MC in children

MCC: S aureus or S pyogenes

highly contagious

honey colored crusting

bullous impetigo has bullae and is caused by S aureus

deeper tissue injury involving skin, SQ, and fascia

MCC: anaerobic bacteria or S pyogenes

painFUL woody indurated plaque

pain out of proportion

dusky purple gray

fever

tachycardia

septic shock

crepitus from methane and CO2 production

RF: immunosuppressed

blastomyces dermatitidis

E and Central US

broad based budding

inhalation w/ hematogenous spread

pulmonary manifestations MC

secondary cutaneous lesion in immunosuppressed → verrucous nodules, abscesses, and ulcers

Candida albicans

oral/esophageal thrush in immunocompromised

• cottage cheese like

vulvovaginitis in DM, abx use

diaper rash

• beefy red w/ satellite pustules and or erosions

endocarditis in IVDA

disseminated in neutropenic pts

chronic mucocutaneous candidiasis

dx: KOH yeast and pseudohyphae

MC in Mississippi and Ohio River Valley

macrophage filled with histoplasma → smaller than RBC

inhlalation of birds and bat feces

fever

skin involvement MC in immunosuppressed

primary cutaneous chancre w/ lymphangitis

pulm manifestations MC

palatal/tongue ulcers

splenomegaly

Paracoccidiodes brasiliensis

MC in Latin America

budding yeast w/ captain’s wheel

• much larger than RBC

inhalation of infected soil

granulomatous ulcerative oropharyngeal and perioral involvement

MC in males

Coccidiodes immitis

SW US, CA

spherule filled w/ endospores

much larger than RBC

inhalation w/ dissemination

verrucous nodules/papules, pustules, abscesses or ulcerative lesions

MC pulmonary manifestations

erythema nodosum or multiforme

arthralgia

can cause meningitis

Sporothrix schenckii

Endemic to Central/South America and Africa

dimorphic

cigar shaped budding yeast w/ branching hyphae and rosettes of conidia

spores traumatically induced usually by thorn

local pustule/ulcer w/ nodules along draining lymphatics → ascending lymphangitis

disseminated in immunocompromised host

dermatophytes: microsporum, trichophyton, epidermophyton

pruritus

tinea capitis: head and scalp

• lymphadenopathy, alopecia, and scaling

tinea corporis: torso

• erythematous scaling, ringworm, central clearing

• acquired from cat or dog

tinea cruris: inguinal area

• does not show central clearing

tinea pedis:

• MC interdigital

• moccasin distribution

• vesicular type

tinea unguium: nails

branching septate hyphae on KOH prep w/ blue fungal stain

Malassezia

yeast like fungus

hypo/hyperpigmented and or pink patches due to degradation of lipids producing acids that damage melanocytes

less pruritic

MC in summer, hot humid weather

dx: spaghetti and meatballs on KOH

EBV

transmission: saliva or blood

infect B cells

irregular, white, painLESS plaques on lateral tongue that cannot be scraped off

RF: immunosuppressed

Coxsackie A16 virus

transmission: fecal-oral, respiratory

prodromal fever and malaise

oval shaped vesicle on erythematous base on palms, soles, and oral cavity

HSV1

clustered vesicles on erythematous base on orolabial region

dormant in sensory dorsal root trigeminal ganglia

transmission: contact w/ saliva

dx: Tzanck

resp secretions

saliva gingivostomatitis

keratoconjunctivitis

herpes labialis

herpetic whitlow on fingers of dentists

temporal lobe encephalitis → sporadic w/ altered mental status, seizures, and aphasia

esophagitis

erythema multiforme

latent in trigeminal

transmission: sexual contact, vertical

viral meningitis

latent in sacral ganglia

painFUL erosion and vesicles

Poxvirus

umbilicated papules

MC in children

STI in adults

Parvovirus B19 virus

single stranded linear (smallest DNA virus)

transmission: resp secretion, blood or placental

prodromal → fever, myalgia, HA

“slapped cheek” w/ maculopapular lacey eruption

in fetus → hydrops fetalis, death

aplastic crises in sickle cell disease

pure RBC aplasia and RA

6-24m of age

higher fever → seizures

diffuse rose-colored macular rash

fever first then rash

MCC: HHV6 and HHV7

Togavirus

infx begins in nasopharynx → LN → viremia

prodrome fever and URI

fine maculopapular rash starting on face and spreads centrifugally to involve trunk and extremities

postauricular LN

arthralgia

blueberry muffin due to extramedullar hematopoiesis

Paramyxovirus

Transmission: resp droplets

prodromal → cough, coryza, conjunctivitis

Koplik spots: bright red spots w/ blue-white center on buccal mucosa

1-2 days later, maculopapular rash that starts at head/neck and spreads downward

lymphadenitis

Warthin-Finkeldey giant cells in background of paracortical hyperplasia

Varicella-Zoster virus

Transmission: resp secretion

prodromal → fever, fatigue, myalgia

multiple crops of lesions

dew drops on rose petals → vesicle on erythematous base

begins on trunk and spreads to face and extremities

complications: encephalitis, pneumonia, Reyes Syndrome

dx: IgG

Varicella-Zoster virus

reactivation from dorsal root/trigeminal ganglion in dermatomal distribution

prodrome → pruritus and pain

painFUL grouped vesicles on an erythematous base

complication: postherpetic neuralgia

Common Warts:

• hyperkeratotic papules w/ pinpoint black dots

• HPV 1/2/4

Condyloma Acuminata:

• genital warts → smooth sessile skin-colored to brown lobulated papules

• HPV 6/11

Cervical Intraepithelial Neoplasm:

• HPV 16/18

T brucei gambiense/rhodesiense

enlarged LN

recurring fever (antigenic variation)

somnolence

coma

transmission: Tsetse fly → painFUL bite

dx: trypomastigote in smear

Trypanosoma cruzi

MC in South America

unilateral periobital swelling → Romana sign

transmission: triatomine, feces deposit in painLESS bite

complication: dilated cardiomyopathy w/ apical atrophy, CHF, megacolon, megaesophagus

dx: trypomastigote in smear

Babesia equi

MC in NE US

fever

HA

hemolytic anemia

RF: asplenia

transmission: Ixodes tick

dx: ring form C1, Maltese cross

Ancylostoma duodenale, Necator americanus

transmission: larvae penetration walking barefoot on contaminated beach

pruritic

serpiginous rash

iron deficiency anemia from sucking blood from intestinal wall

eosinophilia

L donovani, tropica, braziliensis

Visceral → spiking fever, hepatosplenomegaly, pancytopenia

Cutaneous → skin ulcers

transmission: sandfly

dx: macrophages containing amastigotes

trematode fluke

intermediate host: snails

tranmission: contaminated fresh water

lateral spine

hepatosplenomegaly

fibrosis

inflammation

portal HTN

ascites

esophageal varices

terminal spine

squamous cell carcinoma of bladder

painLESS hematuria

pulmonary HTN

Strongyloides Stercoralis

larvae in soil penetrate in feet → larval phase in lung → swallow and molt in adults entering intestinal mucosa and lay eggs → hatch into rhabditiform into intestinal lumen and passed into stool

abdominal pain

diarrhea