1. Barrier- physical, chemical, biologic, immunologic

2. Thermoregulation

3. Sensation

4. Social/psychological

Keratinocytes 80%

Melanocytes 5-10%

Langerhans cells 3%

Merkle cells

This layer of skin is:

- biologically dead, but physiologically active

- acts as a physical barrier

- filters out >80% of UVB radiation

Stratum cornem

This cell type originates in the neural crest but migrates to the basal layer & hair follicle matrix

Melanocytes

Produce melanin & move it into keratinocytes

Eumelanin- brown/black

Phaeomelanin- yellow-red

Eumelanin

Langerhans cells

These cells are:

• mechano-receptor cells
• contain neurosecretory granules
• mediate soft touch

Merkle cells

Which dermal layer is more superficial?

a. papillary dermis

b. reticular dermis

a. papillary dermis

Types 1 & 3

Fx: Skin tension, protection from trauma

In which layer of the skin are blood vessels located?

What are the 2 main functions of blood vessels in the skin?

Dermis

1. Provides nutrients

2. Temperature regulation (via vasodilation & constriction)

1. Hair follicle

2. Sebaceous gland

3. Apocrin gland

What are the 3 growth phases of the hair follicle?What occurs during each phase?

How long does each phase last?

• Anagen- growth, 2-4y (90% of hairs)
• Catagen- rest, 1-2 wks
• Telogen- loss, 5-6 wks

Which gland is responsible for:

holocrine secretion?

merocrine secretion?

Holocrine: sebaceous gland

Merocrine: Eccrine sweat gland

Fungal infection

The Tzanck test is performed to diagnose ___________ infection.

What does it test for the presence of?

Herpes zoster, varicella, HSV

Tzanck cells (multinucleated giant cells)

Warts

Squamous cell carcinoma

Papillomavirus

Keratinocytes

Corn 

(clavus, heloma)

Seborrheic keratosis

Skin tags/acrochordons

Molluscum contagiosum

Actinic keratosis

UVB

B = Burns

UVA

A = Aging

1. UV light exposure
2. Industrial carcinogen exposure (tars & oils)
3. Chronic skin ulcers
4. Immunosuppression

True or False

Basal cell carcinomas are metastatic

False.

"they grow, ulcerate and may invade, but don't metastasize"

Melanocytes

Lentigo

Melasma

(Bzzz: estrogen; pregnancy)

• *Family hx
• Light complexion/poor tanning
• Hx of sunburns
• Precursor lesions
• Multiple nevi
• Xeroderma pigmentosum

Asymmetry

Border (irregular)

Color

Diameter (>6mm)

Enlarging/elevated

upper

hair follicle

Hemangioma

"cherry angioma"

Pyogenic granuloma

Fibrous histiocytoma

(dermatofibroma)

(Bzzz: "dimple sign")

Keloid

Lipoma

Neurofibroma

(Bzzz: neural origin, "button hole sign")

Xanthoma

(there are several different types)

(Bzzz: lipid-laden, xanth=yellow)

Kaposi's sarcoma

(Bzzz: purple)

Dermatitis/eczema

Irritant: caused by a toxic substance on the skin

Allergic: immunologic reaction to something that comes in contact with the skin.

Patch testing

Looking for elevated, erythematous, papules or plaques.

Atopic dermatitis is more prevalent in which age range and socioeconomic classes?

Can you patch test for it?

the very young

85% in first year of life, 95% <5 yo

Higher socioeconomic groups

No. Cannot patch test.

A 1yo patient comes in with a puritic rash in the diaper area. The child also suffers from asthma and hayfever.  

What is your diagnosis?

Atopic dermatitis

(Bzzz: the "atopic triad")

______ _________ is one of the most common causes of disseminated eczema, and is often seen in pts with venous HTN or edema in the lower limbs.

What are some Tx options?

Stasis dermatitis

(stasis- slow blood flow)

Tx: compression stockings, leg elevation

Lichen simplex chronicus

(aka neurodermatitis)

Seborrheic dermatitis

(Bzzz: non-pruritic)

Ulcer

Venous ulcers

Arterial ulcers

Decubitus ulcers

Neuropathic ulcers

(aka Mal perforans)

Non-scarring

Scarring

Telogen effluvium is commonly known as      ______-_______ alopecia.

What are some causes?

Stress-induced alopecia

Childbirth, severe infection, psychological stress, major surgery, thyroid problems, drugs

Most cases of hair loss are due to

__________ ________.

What are some treatment options?

Androgenetic alopecia (AGA) - DHT

Topical minoxidil/Rogaine (40-60%, both sexes)

Finasteride/Propecia (66-83%, men only)

Spironolactone or cyproterone acetate (women)

Hair transplant

Men: Hamilton-Norwood

Women: Ludwig

Trichotillomania

(Bzzz: -mania means an obsession)

________ _____

An autoimmune disorder characterized by well-circumscribed, round patches of non-scarring alopecia with "exclamation-point hairs". May present with erythema and scale and "pitting" of the fingernails.

Alopecia areata

(Bzzz: Exclamation-point hairs)

Note: histological "swarm of bees" around hair bulb)

_______ _____ _____________

Oval areas of scarring alopecia with an erythematous margin, white atrophic center, and a dilated, keratin-filled follicle.

Diagnostic test?

Discoid lupus erythematosus

Biopsy

Infection of the scalp with a dermatophyte fungus

How is this classified? Identified?

Tinea capitis

Classification: how it invades the hair shaft

Ectothrix infection (M. xxx) vs

Endothrix invasion (T. xxx)

Identification: fluorescence under Wood's light

Griseofulvin

Terbinafine

Itraconazole

Selenium sulfide shampoo

Fungal infection of the nail

Most common route of infection?

Onychomycosis

Distal subungual onychomycosis

Terbinafine

Itraconazole

Psoriasis

True or False

Fever, rash, pruritus, and sun sensitivity may be a sign of systemic disease.

True.

Fever & rash

True or False.

Generalized pruritus without a primary skin lesion may indicate systemic disease.

True.

Ex. thyroid, hepatic, hematological, carcinomas, neuropsychogenic, infectious

Infiltration of the skin

Skin changes produced by secretory products of malignancy

Eosiniphilic folliculitis, prurigo nodularis, candidiasis, photosensitivity, molluscum contagiosum, Kaposi's sarcoma, cryptococcosis, psoriasis

Psoriasis

What are some Tx for psoriasis?

(topical & systemic)

Topical: Steroids, calcipotriene ointment, UV light

Systemic: Methotrexate, retinoids, cyclosporine

Dermatophyte infection in the outer keratin layer of the skin. Presents with a pruritic, scaling rash.

Tx?

Dermatophytosis

aka tinea or "ringworm"

Tx: antifungals (no lotrisone or mycolog)

Terbinafine, ketaconazole, itraconazole, Griseofulvin

Pityriasis rosea

Secondary syphilis

Rare skin cancer with three stages, patch→plaque→nodule.

Survival rate decreases with each progression. 

Test for diagnosis?

Mycosis fungoides aka

Cutaneous T-cell lymphoma

Diagnosis: Biopsy

(Can be distinguished from P. rosea b/c it lasts longer than 12 weeks)

Grouped vesicles on an erythematous base.

Often accompanied by a 1-2 day prodrome.

"Balloon cells" present on Tzanck smear.

Herpes simplex virus (DNA virus)

HSV-1 Oral infection

HSV-2 Genital infection

Herpes zoster

• Acyclovir
• Famciclovir
• Analgesics
• Prednisone

Dissemination

Post-herpetic neuralgia

Herpes opthalmicus

Bell's palsy

Large, fragile bullae on the head, neck & extremities caused by Staph aureus. 

Tx?

Bullous impetigo

Tx: topical mupirocin

Systemic cephalosporin, erythromycin, dicloxicillin

Variable rash resulting from antigen re-exposure.

How is this tested?

Allergic contact dermatitis

Patch test

Pemphigus vulgaris

Bzzz: Fragile

(bullous pemphigoid blisters are tense)

Bullous pemphigoid

Abnormal prophyrin metabolism resulting in vesicles, erosions, milia and scarring on the hands. Also results in extra facial hair.

Tx?

Porphyria cutanea tarda

Tx: Phlebotomy, antimalarials

Small, extremely pruritic inflammatory papules and excoriations at skin folds. Caused by Sarcoptes scabiei and has a characteristic "lazy S" burrow.

Diagnostic? Tx?

Scabies

Dx: mineral oil scraping

Tx: Permethrin, lindane, ivermectin

"head lice"

Proper term

Pediculosis capitis

Multiple symmetrical lesions on the extremities

Pruritic, Purple, Polygonal, Papules, Planar

Oral mucosal involvement common.

Lichen planus

Blockage of sweat ducts:

a. as they course through the stratum corneum- small, fragile vesicles, "crystal-like"

b. within the malpighan layer- small, red papules, "prickly heat"

c. deep within skin- large

a. Miliaria crystallina

b. Miliaria rubra

c. Miliaria profunda

1. Papules
2. Pustules
3. Comedones- open & closed
4. Ice-pick scars
5. Post-inflammatory hyperpigmentation
6. Open cystic lesions

Rosacea

(Unlike acne, rosacea doesn't have comedones)

Folliculitis

Impetigo

"Beefy" red erythema with satellite papules and pustules in moist areas.

Tx?

Candidiasis

Tx: Clotrimazole, miconazole, kenaconzole, fluconazole

Tinea versicolor

Acquired condition in which functional melanocytes disappear from affected skin areas; especially in areas of skin movement (joints, periorificial).

Tx?

Vitiligo

Tx: PUVA, grafting

Pityriasis alba

Tuberous sclerosis

The two most common forms of cutaneous drug reactions?

Which groups of patients are at an increased risk for developing an adverse drug reaction?

Morbilliform eruptions- 35-40%

Urticaria- 25-30%

Women, elderly, immunosuppressed,

pts taking multiple medications

Immunologic:

Drugs or their metabolites may act as haptens, inducing a specific cell-mediated humoral response.

Non-immunologic:

Cumulative toxicity, overdose, drug interactions, metabolism alterations

Rash forms in 7-14 days of drug initiation

Pruritic

Erythematous macules & papules

Trunk→extremities (ddx from measles)

Antibiotics

Aspirin & NSAIDs

Anti-epileptics

Viral exanthems

Measles, German measles, HHV6, parvovirus, enteroviruses

Gray-white papules with an erythematous base (Koplik spots) on the buccal mucosa.

Prodrome of Cough, Coryza, and Conjunctivitis.

Eruption begins on head

Complications?

Measles (rubeola)

Cx: encephalitis

Discrete macules and papules, red spots on the soft palate, and tender lymphadenopathy.

Dx test? Cx?

German measles (rubella)

Dx: IgG & IgM Ab

Cx: Arthritis in adults,

congenital rubella syndrome (anencephaly, death)

Herpesvirus type 6 (roseola)

Red cheeks with a "slapped" appearance, followed by a reticulated erythema on the trunk and proximal extremities.

Dx test? Cx?

Parvovirus B19

(erythema infectiosum)

Dx: IgM Ab

Cx: arthritis in adults, aplastic crisis

Vesicular eruption of the palms and soles in conjunction with an erosive stomatitis.

Dx test?

Enterovirus (ECHO/coxsackievirus)

"Hand, foot, and mouth disease"

Dx: viral culture, PCR

Toxic erythema response

Toxic erythema caused by group A strep characterized by a sore throat and "white strawberry" tongue that precedes a rash that changes to a "beefy strawberry" tongue. 

Tx?

Scarlet fever

Tx: Penicillin

SSSS

Staphylococcal Scalded Skin Syndrome

Multisystem disease caused by S. aureus endotoxin. Sudden onset of high fever with vomiting and diarrhea. Progression to shock may occur. 

Scarletiniform exanthem, erythema & edema of palms, soles mucous membranes, & strawberry tongue.

TSS

Toxic shock syndrome

Fever for 5+ days plus at least 4 of the following:

Red, edematous palms & soles

Truncal exanthum

Conjunctivitis

Mucosal erythema

Cervical lymphadenopathy

Kawasaki syndrome

Malar or discoid rash, Photosensitivity, Oral ulcers

Arthritis, ANA

(SLE)

Deep infection of the skin resulting in a localized area of inflammation.

Fever, red, warm, indurated, tender skin.

Etiology?

Cellulitis

GroupA Strep, StaphA, H. influenzae, fungi

Abcess- no pocket

Furuncle- pocketed, around hair follicle

Acute onset of tender, painful, red nodules (often in the shins) precipitated by infections, drugs, sarcoidosis, IBD

Lab tests?

Erythema nodosum

Tests: CXR, throat culture, ASO titers, PPD skin test, skin biopsy

Urticaria

Erythema Multiforme minor

Major = >10%, Stevens-Johnson syndrome

Toxic epidermal necrolysis- >30% BSA Tx: IVIG

Skin lesion associated with lyme disease.

Papule→lg annular lesion,

NO scaling

Erythema migrans

Erythema migrans

or

1 late manifestation (musculoskeletal, nervous, or cardiov involvement) plus infection confirmation

Vasculitis

Leaky vessels

Platelet abnormalities

Thrombosed vessels

Thrombocytopenic purpura

Actinic purpura

Vasculitis

Allergic vasculitis

(Bzz: palpable purpura- vasculitis)

Palpable purpura accompanied by abdominal pain, arthralgia, and hematuria.

Dx finding?

Henoch-Schoenlein purpura

Dx: IgA deposition at blood vessel wall

Rocky Mountain Spotted Fever

Scleroderma

C: flexion contractures, sclerodactyly, mask-face, thin lips, hyper/hypopigmentation, telangietasia, 

S: Esophageal dysfx (>90%), pulmonary fibrosis, cardiac dysfx, renal disease.

Granuloma annulare

Ivory-white papules and atrophic patches often seen in women in the genital area. Labial flattening common.

Increased risk for?

Lichen sclerosis

Squamous cell carcinoma

Necrobiosis lipoidica

Rickettsia rickettsii