5 - Skin, Ears and Eyes

Acne phases

1. Comedonal Acne

   1. Early Comedo: accumulation of epithelial cells and keratin

   2. Late Comedo: accumulation of shed keratin and sebum

2. Inflammatory acne

3. Nodular cystic acne

Three types of folliculitis

1. furuncle

2. carbuncle

3. Stye

Skin and its defenses

Keratin	Provide protection, ability to withstand damage, prevent penetration of microorganism, and give skin its water-repellent property
Sloughing-off of skin	Removes dead cells and microorganisms from the skin
Antimicrobial peptides	Disrupt negatively charged bacterial membrane
Sebum	Has low pH (acidic), and high concentration of lipids
Sweat	Has low pH (acidic), high in salt, provide washing effect
Lysozyme	Breaks down peptidoglycan layer; found in saliva, swear, and tears
IgA	Attacks foreign invaders or microorganisms

Eyes and its defenses

Tears	Provide washing effect for the eyes; contain lysozyme, sugar, and lactoferrin
Mucus	Produced by conjunctiva for lubrication; to avoid abrasions or friction
Blinking	Mechanism to expel foreign matter from the eyes; facilitates lubrication

Ears and its defenses

Hair	Prevent foreign material or objects from entering the ears
Cerumen	Prevents damage to the delicate skin inside our ears

S. aureus virulence factors

Leukocidin	Kills WBC
Coagulase	Produce clots in capillaries
Epidermolytic toxin	Separates layers of epidermis
Penicillinase	Disrups internal structure of penicillin
TSS toxin	Stimulate T cells to produce cytokines
Protein A	Inhibit phagocytosis
Capsule	Inhibit phagocytosis
Protease	Degrades collagen and other tissue proteins
Lipase	Breaks down fat
Hyaluronidase	Breaks down hyaluronic acid

S. pyogenes virulence factors

M protein	Prevent activation of complement and allow phagocytosims
Erythrogenic toxin	Produce erythematous reaction
TSS toxin	Stimulate T cells
Streptolysin S and O	Cause RBC hemolysis
Deoxyribonuclease	Degrades DNA
Streptokinase	Dissolves blood clot
Hyaluronidase	Break down hyaluronic acid

bacterial infections of the skin

1. acne

2. folliculitis

3. scarlet fever

4. erysipelas

5. toxemias

6. impetigo

7. cellulitis

8. necrotizing fascitis

9. pseudomonas dermatitis

bacterial infections of the ears

1. otitis externa

2. otitis media

bacterial infections of the eyes

1. bacterial conjunctivitis

2. neonatal conjunctivitis

3. ocular trachoma

DESCRIPTION	S/X
Sweat and dead cells trapped in pores, digested by lipase (from bacteria) -> inflammation

CONDITION	CAUSATIVE AGENT	TREATMENT
Acne	Propionibacterium acnes	topical agents, topical or oral antibiotics, oral contraceptive pills

DESCRIPTION	S/X
Infection of hair follicles	Lesion w/ fluid and pus in hair follicles

CONDITION	CAUSATIVE AGENT	TREATMENT
Folliculitis	Staphylococcus aureus	Antistaphylococcal drugs (2nd gen penicillin, 1st and 2nd gen cephalosporins)

DESCRIPTION	S/X
Infection of pharyngitis through droplet or direct contact	goose-flesh or sandpaper-like red maculopapular rash severe sore throat

CONDITION	CAUSATIVE AGENT	TREATMENT
Scarlet fever	Staphylococcus pyogenes	Penicillin, Cefalexin

DESCRIPTION	S/X
St. Anthony’s fire / Ignis sacer Infection of the dermal layer	Early: Edema and redness of skin in portal of entry (wound)   Late: lesions spreading outward, sepsis

CONDITION	CAUSATIVE AGENT	TREATMENT
Erysipelas	Staphylococcus pyogenes	Penicillin, Cephalosporins

DESCRIPTION	S/X
Common in newborn and babies; following nasal surgery, surgical incisions	Sunburn like rash and hypotension -> shock and organ failure

CONDITION	CAUSATIVE AGENT	TREATMENT
Toxic Shock Syndrome	Staphylococcus aureus and Streptococcus pyogenes	Cloxacillin and cefalexin

DESCRIPTION	S/X
Ritter’s disease or Pemphigus neonatorum; Common in newborn and babies	Scalded skin, painful nose, mouth and genitalia

CONDITION	CAUSATIVE AGENT	TREATMENT
Scalded Skin Syndrome	Staphylococcus aureus	Cloxacillin and cefalexin

DESCRIPTION	S/X
Precipitated by minor breaks in skin; common in preschool children	Blisters

CONDITION	CAUSATIVE AGENT	TREATMENT
Impetigo	Staphylococcus aureus and Streptococcus pyogenes	Topical mupirocin or pleuromutilin Oral cephalexin

DESCRIPTION	S/X
Parenteral implantation of bacteria to dermis and sc; Common in immunocompromised px and varicella px	red lines leading away from swelling of lymph nodes

CONDITION	CAUSATIVE AGENT	TREATMENT
Cellulitis	Staphylococcus aureus and Streptococcus pyogenes	Cefalexin Surgical debridement

DESCRIPTION	S/X
Flesh eating disease; affects fascia

CONDITION	CAUSATIVE AGENT	TREATMENT
Necrotizing fasciitis	Staphylococcus aureus and Streptococcus pyogenes	Broad spectrum antibiotic Surgical debridement Amputation

DESCRIPTION	S/X
Hot tub rash   Contracted in swimming pools, hot tubs and sauna   Inhibits elongation factor 2	Colored pus (blue-green or yellow green); grape-like odor

CONDITION	CAUSATIVE AGENT	TREATMENT
Pseudomonas dermatitis	Pseudomonas aeruginosa	Benzoyl peroxide; Ureidopenicillins

DESCRIPTION	S/X
Swimmer’s ear   Swimming in polluted waters, water trapped in ears, cotton swabs   Inhibits elongation factor 2

CONDITION	CAUSATIVE AGENT	TREATMENT
Otitis externa	Pseudomonas aeruginosa	Hydrogen-peroxide water mixture Antibiotic ear drops: ciprofloxacin + hydrocortisone

DESCRIPTION	S/X
Inflammation of middle ear  entry to eustachian tube   Bottle feeding	Ear pain and fluid in ears

CONDITION	CAUSATIVE AGENT	TREATMENT
Otitis media	Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis	Analgesic (paracetamol, ibuprofen) Severe: amoxicillin

DESCRIPTION	S/X
Madras eye, Bombay eye, pink eye   Contact lens, accidental inoculation of eye	Redness and swelling of eye, milky discharge

CONDITION	CAUSATIVE AGENT	TREATMENT
Bacterial conjunctivitis	Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Moraxella sp.	Broad spectrum antibiotics (ciprofloxacin or chloramphenicol eye drops)

DESCRIPTION	S/X
Redness and swelling of eye, milky discharge

CONDITION	CAUSATIVE AGENT	TREATMENT
Neonatal conjunctivitis	Chlamydia trachomatis, Neisseria gonorrhoeae	Prevention: tetra or erythromycin or 1% silver nitrate eyedrops If gonorrhoeae: ceftriaxone If trachomatis: tetracycline

types of acne and their treatment

DESCRIPTION	S/X	TREATMENT
Comedonal acne	Early: accumulation of epithelial cells and keratin Late: accumulation of shed keratin and sebum	Azelaic acid, salicylic acid and retinoids
Inflammatory acne	Production of pus	benzoyl peroxide/retinoids + clindamycin/erythromycin
Nodular cystic acne	Widespread formation of cyst at deeper layer of skin (dermis)	Isotretinoin (alt for preg: clindamycin/erythromycin)

types of folliculitis

Furuncle	Inflammation of a single hair follicle
Carbuncle	Cluster or group of furuncles with draining pus and generalized fever
Sty	Infection of follicle of eyelash Hordeolum – at the edge of the eyelid Chalazion – of the oil gland beyond the eyelid

types of impetigo

Non-bullous	honey crust / flaky scabs
Bullous	fluid filled lesion

DESCRIPTION	S/X
Greatest single cause of blindness   Sharing personal objects	Conjunctivitis, mild discharge, pebbled rough appearance of upper eyelid, pannus

CONDITION	CAUSATIVE AGENT	TREATMENT
Ocular trachoma	Chlamydia trachomatis (Serovar A,B,C)	Azithromycin or Erythromycin

Gram-positive, highly heat-resistant, golden colonies, w/ catalase, coagulase, Novobiocin sensitive, positive on hemolysis on blood agar

Staphylococcus aureus

Gram-positive, with white-gray agar and catalase, novobiocin sensitive, negative on hemolysis on blood agar

Staphylococcus epidermidis

Gram-positive, with white-gray agar and catalase, novobiocin resistant, negative on hemolysis on blood agar

Staphylococcus saprophyticus

Gram-positive, lancefield group A, catalase negative, beta, bacitracin-sensitive

Streptococcus pyogenes

Gram-positive, lancefield group B, catalase negative, beta, bacitracin-sensitive

Streptococcus agalactiae

Gram-positive, lancefield group D, catalase negative, gamma, grows in 6.5% NaCl

Enterococcus faecalis

Gram-positive, catalase negative, alpha, bile-soluble, optochin-sensitive

Streptococcus pneumoniae

Gram-positive, catalase negative, alpha, bile-insoluble, optochin-resistant

Streptococcus viridans

Gram-negative aerobic rods found primarily in soil and water

Pseudomonas aeruginosa

Gram-negative aerobic coccobacilli, encapsulated or non-encapsulated

Haemophilus influenzae

Gram-negative cocci

Moraxella sp

Gram-negative, obligate intracellular parasite

Chlamydia trachomatis

Non-motile and non-spore forming cocci; diplococcus, kidney-shaped; with fimbrae

Neisseria gonorrhoeae

drug of choice for pseudomonas dermatitis

ureidopenicillins

2nd gen penicillin

Methicillin, Nafcillin, Oxacillin, Cloxacillin, Dicloxacollin

1st gen cephalosporin

1st PhD in AZtrology: DR. ALEX RAD

1. Cefazolin

2. Cefadroxil

3. Cephalexin/Cefalexin

4. Cephradine

2nd gen cephalosporin

The FURy FACulty FAMily not giving a FOX and spilling TEa like a PRO

1. Cefuroxime

2. Cefaclor

3. Cefoxitin

4. CefoTEtan

5. Cefprozil

3rd gen cephalosporin

TRI to FIX TAXes. DIME. PERA. DINIR.

1. ceftriaxone

2. cefixime

3. cefotaxime

4. ceftazidime

5. cefoperazone

6. cefdinir