Eczema

• Also known as atopic dermatitis.
  
• Common disease associated with other atopic diseases such as asthma and rhinitis.
  
• Characterized by itchy, inflamed skin.
  
• Prutic lesions result in thickening and lichenification of skin with increased skin markings.

Contact dermatitis

• Inflammatory reaction of the skin precipitated by contact with irritant or allergen
• Vesicles in the epidermis
• Perivascular inflammation

Psoriasis

• Well defined, slightly raised, hyperkeratotic (scaling) plaques.
• Scratching the lesion reveals small bleeding points, which is a specific sign on the disease.
  
• The stratum corneum thickens, and erythamatous plaques with silvery scales result.
  
• Lesions are often on extensors (elbows, knees), scalp, and intergluteal cleft. 

Uriticaria

• The primary lesion is the wheal or hive.
  
• The epidermis is normal, the dermis shows papillary edema.
  
• Inflammatory cells may be found surrounding the dilated blood vessels.
  
• Release of substances such as histamine change the vascular permeability and produce dermal edema.

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Impetigo

• Highly contagious, superficial skin infection caused  by group A beta hemolytic strep, staph, or both.
  
• More common in summer.
  
• Primary lesion is vesicopustule
• Once it ruptures it produces a honey colored crust surrounded by a rim of erythema.

Erysipelas

• "Red skin" due to acute streptococcus infection of dermis
• Inflammation extending into underlying fat flap

Shingles

• Intraepidermal vesicular eruption occurring in a dermatomal distribution.
  
• Bullae and multinucleated giant cells are present in the epidermis with perivascular inflammation

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Dermatophyte infection

• Dermatophytes are fungi that require keratin for growth and cause superficial infections of the skin.
  
• They cause “tinea” infections (ringworm)
  
• Involve hairless areas of skin including the body, groin, nails, and head.

Tinea versicolor

• Common superficial fungus infection of the skin
  
• Causes hypopigmented, slightly scaly macules on the trunk, neck, and upper arms (dark on light-skinned individuals, light on dark-skinned individuals)

1. Urticaria, angioedema
2. Hemoylsis, purpura
3. Vasculitis, serum sickness, urticaria
4. Contact dermatitis

Cellulitis

Occurs when bacteria invade normal or broken or normal skin and start to spread under the skin into the soft tissues. 

Erythema multiforme

• Immunologic reaction in the skin triggered by various agents including
  
  • viruses
  • bacteria
  • drugs (penicillin and sulfonamides)
    
  • x-rays.
    
• The condition includes a variety of lesions including papules, bullae, plaques and “target lesions”.
  
  • Target lesions have three zones of color: a central dark area is surrounded by a zone of reactive pallor that is rimmed by a think area of erythema.
    
  • Target lesions are typically seen on palms and soles.
    

Steven-Johnson Syndrome

Severe form of erythema multiforme that involves the mucous membranes.

Vitilgo

• Depigmented macules appear on the face, hands, feet, extensor surfaces
  
• May coalesce into extensive areas that lack melanin.
  
• Pale areas are called vitiligo

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Seborrheic dermatitis

•  Papulosquamous disorder associated with epidermal hyperplasia and flakey scales.
  

• The lesions have a greasy looking scale in a seborrheic distribution (sebaceous glands):
  

  • scalp,
    

  • eyebrows,
    

  • nasolabial fold,
    

  • perioral area,
    

  • midchest

  • groin.

Seborrheic keratosis

• Well defined lesions in any area of the body exposed to UV light.
  
• The lesions have a fissured surface
  
• Result from a failure of keratinocytes to mature normally, which produces and accumulation of immature cells in the epidermis.

Actinic keratosis

• Superificial, flattened papules covered by a dry scale.
  
• Multiple, round or irregular, pink, tan or grayish.
  
• Appears on sun exposed skin of older, fair skinned persons.

Nevus

• AKA mole
  
• Usually appears in the first few decades.
  
• Round or oval shape, sharply defined borders,
  
• Uniform color esp tan or brown
  
• Diameter less than 6 mm, flat or raised surface.
  
• Changes in these features raise the suspicion of atypical nevi or melanoma.
  
• Atypical nevi often appear on the trunk.

Basal cell carcinoma

• Malignant but grows slowly and seldom metastasizes.
  
• Most common in fair skinned people over 40 and usually appears on the face.
  
• An initial translucent nodule spreads, leaving a depressed center and a firm, elevated border.

Squamous cell carcinoma

• Usually appears on sun exposed skin of fair skinned adults older than 60.
  
• May develop in an actinic keratosis.
  
• Grows more quickly than a basal cell carcinoma, is firmer, and looks redder.
  
• Face and back of the hand are often affected.

Melanoma

ABCDE

• Asymmetrical shape
• Irregular border
• Change in color (uneven distribution)
• Diameter (>6mm)
• Evolving (changes over time)

• Color – Look for increased pigmentation, loss of pigmentation, redness, pallor, cyanosis, and yellowing of skin. Hypopigmentation is less color than normal. Depigmentiation is the lightest skin can get. Hyperpigmented means more color (darker) than normal.
• Moisture – dryness, sweating, and oiliness
• Temperature – generalized warmth of coolness of the skin
• Texture – roughness and smoothness
• Mobility and Turgor – note ease with which the skin lifts up (mobility) and speed with which it returns back into place (turgor)
• Lesions – anatomic location, patterns and shapes, distrubution on body, color of lesions.

What are the "three symptoms of the skin"?

1. Pain
2. Itching
3. "Strange" (neuralgia)

Discrete, solid, elevated body (less than 1 cm in diameter)

• Solid, raised lesion >1cm diameter (due to width).
• Flattened top (like plateau)
• Typically arises from fast growing papule.

• Vesicles: clear fluid, less than 1 cm
• Bullae:  clear fluid, more than 1 cm
• Pustules: cloudy fluid, size unspecified

Macule: A flat, less than 1 cm area of skin or mucous membranes with different color from surrounding tissue.

Patch: Same as above, greater than 1cm.

1. Scale
2. Pigmentations
3. Ooze and weep
4. Verrucous changes (wart-like)
5. Crust
6. Lichenification (accentuated skin lines)
7. Membrane
   
8. Atrophy
9. Scar
   
10. Maceration (bandaid left on too long)

Ulcer: wide and deep (ocean)

Erosion: wide and shallow (pond)

Fissure: narrow and deep (grand canyon)

• Annular (round, edge different from center – donut)
• Targetoid (round, concentric circles – target)
• Serpiginous (snake like)
• Scalloped (formed by multiple circles coalescing) 
• Dome-shaped