Skin and Eye Diseases

3 functions of the skin

Thermoregulation

Sensory function

Physical protection

3 layers of the skin

Epidermis- outmermost layer, contains keratin

Dermis- thickest layer, contains nerves, blood vessels, hair follicles, oils and sweat glands

Subcutaneous layer- contains fat

Host defenses

Physical barriers- keratin, layers of skin, tight junctions, perspiration

Chemical barriers- salt, lysozyme, IgA antibodies, low pH, antimicrobial peptides

Biological protection- normal microbiota

Pathogenic strategies

Breach of structures- wounds, hair follicles

Secretion of enzymes- IgA protease

Modification of antigens- antigenic drift

Macules

Flat red spots- freckles

Papules

Small, raised bumps- acne

Pustules

Papules filled with pus- pimples

Vesicles

Small, fluid filled blisters- herpes

Bullae

Large, fluid filled blisters- burns

Staphylococcus aureus infections

Boils

Staphylococcal scalded skin syndrome

Streptococcus pyogenes infection

Erysipelas

Scarlet fever

Both Staphylococcus aureus and Streptococcus pyogenes infections

Cellulitis

Impetigo

Necrotizing fasciitis

Common features of Staphylococcus aureus and Streptococcus pyogenes

Responsible for wide range of skin diseases

Superficial and deep

gram positive

B-hemolytic

Spread through close contact

Damage to skin facilitates an infection

Staphylococcus aureus

• Resistant to penicillin (beta-lactam antibiotics)

• Erythogenic and dermolytic toxins

Streptococcus pyogenes

• Sensitive to bacitracin

• Different kind of erythrogenic toxin- Group A strep

Cellulitis

Symptoms: Edema/swelling, erythematous rash with diffuse borders, common in immune compromised people- type 2 diabetics

Treatment: Oral antibiotics, IV vancomycin in severe cases

Prevention: Reducing the risk of infection by keeping any cuts, abrasions, infected hair follicles clean and day with CHG, apply clean dry dressing

Impetigo

Symptoms: Oozing vesicles that dry to form honey- colored crusts

Treatment: Cleaning with antibacterial soap, topical mupirocin application, oral antibiotics based on severity.

Prevention: Avoiding those who are not infected, proper hand hygiene

Necrotizing fasciitis

Symptoms: Intense pain at infection site, reddening/purple/bronze mottled rash, fever, tissue destruction, shock, organ system failure, death

Treatment: Agressive antibiotic therapy, hyperbaric therapy, surgical debridement, amputation

Prevention: Proper wound care, timely medical attention, hygeine and infection control

Boils/Folliculitis (furuncles and carbuncles)

Symptoms: Entire follicle is infected resulting in enlarged, painful pustules

Treatment: Washing with antibacterial soap, topical and/oral antibiotics, incision and drainage if necessary

Prevention: Proper hygiene, maintain healthy skin

Staphylococcal scalded skin syndrome

Symptoms: Prevalent in newborns or children under two, very painful, fever, rough erythematous rash, desquamation and bullae formation

Treatment: IV nafcillin, supportive care, topical care similar to burn therapy

Prevention: Avoiding those with staph infections, cleaning any break in the skin appropriately, proper hand hygiene

Erysipelas

Symptoms: Fever, edema, painful, itchy erythema with delineated border (defined border)

Treatment: Oral or I M penicillin with most cases

Prevention: Keeping cuts, abrasions clean and dry, clean with CHG, apply clean dry dressing.

Scarlet fever

Symptoms: Florid rash from erythrogenic toxin, strawberry tongue, circumoral pallor, pastia lines, general systemic upset.

Treatment: B-lactam antibitoic, symptomatic treatment with Motrin and Tylenol

Prevention: Treating strep throat immediately and correctly

Pseudomonas aeruginosa

• Gram negative bacillus

• Direct contact or fomite transmission

• Moist skin conditions or repeatedly wet skin

• Fruity odor (trimethylamine), green pus or discoloration of area (pyocyanin).

• Treatment: Antibotic treatment according to sensitivity

• Prevention: Limit water exposure/submergence of skin

Pseudomonas aeruginosa infections

Hot tub folliculitis

Green nail syndrome

Ecthyma gangrenosum

Opportunistic secondary skin infections

Hot tub folliculitis

Symptoms: Maculopapular and pustular lesions on wet areas of the body such as parts covered by a bathing suit.

Treatment: Antibiotics according to sensitivity

Prevention: Limit hot tub use, keep water clean, dry off completely.

Green nail syndrome

Symptoms: Blue-green nail discoloration due to infection of the nail bed by P.aeruginona and pyocyanin secretion

Treatment: Antibiotics

Prevention: Limit water exposure/submergence of skin

Ecthyma gangrenosum

Symptoms: Painless red macules that quickly evolve into hemorrhagic pustules and then into gray-black sloughing scabs with a reddish halo

Treatment: Aggressive and immediate antibiotic therapy is essential

Prevention: Limit water exposure/submergence of skin

Opportunistic secondary skin infections

Symptoms: Black and purple skin discolorations with sloughing scab formation

Treatment: Antibiotics

Prevention: Careful monitoring of hospitalized patients with epidermal damage (burns, indwelling lines), malignancies, and diabetes

Gas Gangrene

Etiology: Clostridium perfringens

Symptoms: Excruciating pain, gas bullae, myonecrosis (rapid destruction of muscle cells)

Treatment: Surgical, drug, and hyperbaric treatments

Prevention: Proper wound care, Anti-toxin vaccine

Acne Vulgaris

Etiology: Propionibacterium acnes

Symptoms: Comedones, papules, pustules, nodes/cysts on face, shoulders, back, and/or chest

Treatment: Topical and/or oral antibiotics, Vitamin A derivatives

Prevention: No great and consistent options; low sugar diet, gentle daily cleansing, avoidance of oily skin products

Cutaneous Anthrax

Etiology: Bacillus anthracis

Symptoms: Black eschar

Treatment: Aggressive antibiotic therapy immediately upon discovery of infection

Prevention: Avoiding reservoirs where it’s found (soil). This is the one people would mail to high profile politicians in envelopes.

Chickenpox

Etiology: Varicella zoster virus (VZV)

Symptoms: Itchy, vesicular rash emerging in waves, forming scabs as vesicles rupture; fever, headache, malaise

Treatment: Symptomatic therapy, post exposure vaccination if given within 72 hours of exposure, Acyclovir for rare severe complications

Prevention: Immunization, avoidance of infected people, good personal hygiene.

Measles

Etiology: Morbillivirus

Symptoms: Koplik spots, itchy confluent maculopapular rash and fever

Treatment: Comfort measures for fever and rash, close monitoring for more severe complications (otitis media, pneumonia, encephalitis

Prevention: MMR vaccine

Rubella

Etiology: Rubivirus

Symptoms: Fine pink, spreading maculopapular rash, congestion, lymphadenopathy, and eye inflammation. Verticle transmission may lead to deafness, cataracts, heart defects, microcephaly, blueberry muffin rash, and miscarriage

Treatment: Bed rest, hydration, and fever reducers

Prevention: MMR vaccine

Roseola (baby measles or 6th disease)

Etiology: Rubivirus

Symptoms: High fever, spreading pink Maculopapular patches on trunk; rash blanches when pressure is applied.

Treatment: Symptomatic treatment for comfort

Prevention: No vaccine

Fifth disease

Etiology: Parvovirus B19

Symptoms: Bright red exanthem, most prominent on cheeks

Treatment: Symptomatic treatment for comfort

Prevention: No vaccine, avoidance of infected people

Hand, foot, and mouth disease

Etiology: Coxsackievirus A19

Symptoms: Painful red blisters in mouth and on palms and soles, alarmingly high fever, potential seizure

Treatment: Comfort measures, avoidance of crunch or rough foods, promote fluid intake

Prevention: No vaccine

Shingles

Etiology: Varicella zoster virus (VSV)

Symptoms: Tingling, asymmetric vascular rash runs along nerve, painful

Treatment: Acyclovir prescribed within 72 hours of symptom onset; symptomatic therapy

Prevention: Shingles immunization; varicella childhood immunization to prevent lysogeny

Warts

Etiology: Human papillomavirus (HPV

Symptoms: Skin raised with bumpy projections or small, flat elevations

Treatment: Chemical or physical removal

Prevention: Avoidance of direct contact and fomites

Smallpox

Etiology: Variola major, ariola minor viruses

Symptoms: Large, indented lesions filled with viscous fluid; emerge around mouth, spread over face and head to trunk and then extremities.

Treatment: No cure; comfort measures. antibiotics administered to minimize secondary bacterial infections of the damaged skin.

Prevention: Vaccines for those at high risk of infection

Candidiasis (vaginal yeast infections, oral thrush, yeast diaper rash)

Etiology: Candida albicans

Symptoms: Edema, irritation, and erythema that may not have vesicles

Treatment: Topical or oral antifungals depending upon infection severity

Prevention: Prophylaxis, strict adherence to hygiene protocols.

Dermatomycoses

Etiology: Assorted tinea infections

Symptoms: Hair loss, redness, itching

Treatment: Superficial (tinea)

Prevention: Avoid contact with infected persons and most environments

Pediculosis (crabs)

Etiology: Pediculus humanus

Symptoms: Scratch marks on the scalp and nape of neck; erythematous papules on body; purpuric spots on thighs, buttocks, or abdomen; generally itchy

Treatment: Lindane or malathion, removal of arthropods, nitpicking with a fine-tooth comb, whole home treatment

Prevention: Avoidance of infested patients, thorough fomite decontamination

Scabies

Etiology: Sarcoptes scabiei

Symptoms: Intensely itchy lesions due to allergic reaction to mite saliva.

Treatment: Prescription of 5% permethrin cream; comfort measures including Benadryl and/or OTC anti-itch creams

Prevention: Avoidance of infested patients, meticulous fomite decontamination

Defenses of the eye

Eyelids, lashes

Microbiota

Tears- high NaCl concentration, lactoferrin, lysozyme, IgA

Conjunctivitis

Etiology: Multiple etiologies

Symptoms: Bright red conjunctiva, itching, tearing, discharge, and eyelid edema.

Treatment: Antibiotic therapy for bacterial infections: comfort measures for bacterial and viral infections.

Prevention: Meticulous hand hygiene; patient isolation; decontamination fomites.

Blepharitis

Etiology: Staphylococci, Propionibacteriums

Symptoms: Inflammation of the eyelids close to the lash line, edema, trichiasis, frequent relapses, formation of a sty

Treatment: Eye or oral antibiotic

Prevention: Don’t touch eye

Keratitis

Etiology: Pseudomonas, Herpes virus (HSV-1), Acanthamoeba

Symptoms: Inflammation of the cornea, photophobia, blurry vision, corneal ulceration

Treatment: Surgery, medication

Prevention: Consistent, correct cleaning of contact lenses; patient education

Trachoma

Etiology: Chlamydia trachomatis

Symptoms: Conjunctivitis, followed by damage to oil glands that impacts eyelash direction. Corneal abrasions by eyelashes resulting in blindness

Treatment: Azithromycin, doxycycline

Prevention: Clean water supplies, elimination of flies