PP's derm

acne vulgaris

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

• etiology:

  • sebum/androgen production

  • abnormal keratinocyte desquamation

  • C. acnes colonization of pilosebaceous unit

  • inflammation

anthrax

• 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

Bacillary Angiomatosis

• Bartonella henselae or quintana

• erythematous violaceous papules to nodules

• RF: immunocompromised

• Dx: Warthin-Starry silver stain

Botulism

• 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

Ehrlichiosis

• Ehrlichia chaffeensis

• vector: tick

• fever, HA, malaise

• maculopapular rash

• leukopenia

• thrombocytopenia

• increased ALT/AST

• monocyte w/ morulae B in cytoplasm

  • mulberry like inclusion

Leprosy

• 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

Lyme Disease

• 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

RMSF

• Rickettsia rickettsii

• vector: tick

• MC in South Atlantic, esp NC

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

• HA

• fever

• rash

Staphylococcus

• 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

Scalded Skin Syndrome

• fever

• generalized erythematous rash

• sloughing of upper layers of epidemis

• (+) Nikolsky sign

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

• (-) blood culture

Toxic Shock Syndrome

• severe multisystem disease w/ cutaneous and internal involvement

• menstrual: young women w/ superabsorbent tampons

• nonmenstrual: nasal packing

• fever

• hypoTN

• scarlatiniform eruption

• palmoplantar desquamation

Erysipelas

• sharply defined fiery red plaque

• superficial variant of cellulitis in upper-mid dermis

• (-) culture

• increased DNase B and ASO titer

• MC: streptococcus pyogenes

Scarlet Fever

• 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

Primary Syphilis

• painLESS chancre

• dark field microscopy to visualize treponemes

• (+) VDRL in 80%

Secondary Syphilis

• 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

Tertiary Syphilis

• 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

Congenital Syphilis

• 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

Tetanus

• 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

Endemic Typhus

• Rickettisia typhi

• vector: flea

• fever

• erythematous macules and papules

• rash starts centrally and spreads out

• sparing palms and soles

Epidemic Typhus

• Rickettsia prowazekii

• human body louse

• fever

• erythematous macules and papules

• rash starts centrally and spreads out

• sparing palms and soles

cellulitis

• 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

impetigo

• 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

Necrotizing Fasciitis

• 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

Blastomycosis

• 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

Candidiasis

• 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

Histoplasmosis

• 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

Paracoccidiodomycosis

• 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

Coccidiodomycosis

• 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

Sporotrichosis

• 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

tinea

• 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

tinea pityriasis versicolor

• 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

hairy leukoplakia

• EBV

• transmission: saliva or blood

• infect B cells

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

• RF: immunosuppressed

Hand, Foot, Mouth disease

• Coxsackie A16 virus

• transmission: fecal-oral, respiratory

• prodromal fever and malaise

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

Herpes Labialis

• HSV1

• clustered vesicles on erythematous base on orolabial region

• dormant in sensory dorsal root trigeminal ganglia

• transmission: contact w/ saliva

• dx: Tzanck

HSV1

• 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

HSV2

• transmission: sexual contact, vertical

• viral meningitis

• latent in sacral ganglia

• painFUL erosion and vesicles

Molluscum Contagiosum

• Poxvirus

• umbilicated papules

• MC in children

• STI in adults

5th disease/Erythema Infectiosum

• 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

Roseola

• 6-24m of age

• higher fever → seizures

• diffuse rose-colored macular rash

• fever first then rash

• MCC: HHV6 and HHV7

Rubella

• 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

Measles

• 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

• 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

Herpes Zoster

• 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

Verrucae Warts

• 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

African Trypanosomiasis - African Sleeping Sickness

• T brucei gambiense/rhodesiense

• enlarged LN

• recurring fever (antigenic variation)

• somnolence

• coma

• transmission: Tsetse fly → painFUL bite

• dx: trypomastigote in smear

American Trypanosomiasis - Chagas Disease

• 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

Babesiosis

• Babesia equi

• MC in NE US

• fever

• HA

• hemolytic anemia

• RF: asplenia

• transmission: Ixodes tick

• dx: ring form C1, Maltese cross

Cutaneous Larva Migrans - Hookworms

• 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

Leishmaniasis

• L donovani, tropica, braziliensis

• Visceral → spiking fever, hepatosplenomegaly, pancytopenia

• Cutaneous → skin ulcers

• transmission: sandfly

• dx: macrophages containing amastigotes

Schistosomaiasis - Swimmer’s Itch

• trematode fluke

• intermediate host: snails

• tranmission: contaminated fresh water

S Mansoni

• lateral spine

• hepatosplenomegaly

• fibrosis

• inflammation

• portal HTN

• ascites

• esophageal varices

S Haematobium

• terminal spine

• squamous cell carcinoma of bladder

• painLESS hematuria

• pulmonary HTN

Threadworm

• 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