Dermatitis

Definition

• Dermatitis is defined as:

1. Ill Defined
2. Scaly
3. Red/"inflamed"

• Examples:

Dermatitis
Not Dermatitis Well demarcated This is psoriasis
Acute Dermatitis Often comes with excoriations due to itching
Chronic Dermatitis Lichenification Post-inflammatory dyspigmentation

Atopic Dermatitis

• Stages:

1. Infantile (to age 1) - extensor: face, scalp
2. Childhood - lichenified plaques and patches: neck, extremities with flexual accentuation
3. Adult - Hand and periorbital areas

• Varies with extremes of temperature (seasonal)
• Complications
  • Seconary bacterial infection (Staph aureas, GAS)
  • Seconary viral infection (HSV - eczema herpeticum)
  • Keratoconus (eye rubbting)
  • Pruritis
  • Scarring/Lichenification
  • Pigment changes.
• Tx:
  • Course: Improves with age - 70% outgrow by late childhood
  • Skin Care: Moisturize with thick lubricants & emollients
  • Steroids: Appropriate strength topical steroids
    • Topical immunomodulators - Tacrolimus, Pimecrolimus
  • Itching: Oral H1 blockers (antihistamines) for itch
  • Infection: Oral and topical abx for infections
  • If SEVERE: treat with systemic immunosuppressants like methotrexate & azathioprine.

Contact Dermatitis

• Occurs in contact with substance (can be papullar - see image)
• Two forms: Allergic and Irritant...

1. Allergic Contact Dermatitis

   • Only people with allergy react 
   • i.e. poison ivy
   • Common Allergens:
     • Neomycin - topical OTC medication
     • Ethylenediamine
     • Nickel (costume jewellery, metal products)
     • Lanolin - topical moisturizers
     • Formaldehyde - preservative
     • Quaternium-15 - A preservative
     • Benzacaine - A local ester anesthetric (anti-itch medications)
     • PPD (Paraphenylenediamine) - a tar derivative in hair dyes
     • Rubber / Latex
     • Poison Ivy
   • Poison Ivy Dermatitis:
     • Reaction to substance Urushiol (also in poison oak, poison sumac, cashew nut oil, gingko biloba)
     • Treatment
       • Compresses,
       • Topical Steroids,
       • Short course oral steroids
       • Oral H1 antihistamines
       • Avoid cross reactors

2. Irritant Contact Dermatitis

   • Almost everyone who comes in contact would react
   • i.e. hydrogen peroxide

Seborrheic Dermatitis

• Common: dandruff
• Lots of sebum production - seborrhea, but seborrheic dermatitis has nothing to do with sebum.
  • Due to Malasseiza furfur yeast
  • Can be severe with HIV and Parkingson's
• Greasy to white flakes, itch +/- erythema
• Tx:
  • Shampoos with selenium sulfide
  • Topical antifungal (azole group)
  • Short course of oral antifungal (azole group)

Stasis Dermatitis

• Persistent skin inflammation of lower legs with brown pigmentation, erythema, xerosis, and scaling
• Associated with venous insufficiency
• Can be complicated by ulceration, and bacterial infections

Dyshidrotic Eczema

• acute "pseudovesicular" lesions, coalesce into plaques, which dry and develop scales
• VERY itchy
• Usually due to frequent hand washing
  • Common in occupations with frequent hand washing (i.e. healthcare)
• Lesions heal with desquamation (peeling) and can lead to chronic lichenification
• Sites: palms, soles, dorsal surfaces of hands and feet.
• Tx:
  • Skin Care: Moisturize frequently especially after handwashing
  • Steroid: Topical steroid (high potency)
    • Injection of corticosteroids
  • If SEVERE: oral prednisone
  • Infection: abx.

Diaper Dermatitis

• Inflammation 2ndary to candidiasis
• "Diaper dermatitis" is not a diagnosis, cause can be:
  • Atopic dermatitis
  • Seborrheic dermatitis
  • Irritant from voiding

Seborrheic Dermatitis

• Oily crust, often on face, between eye brows etc..
•     

Other Dematitis Types

• Asteotic Dermatitis
  • Usually in older individuals "dried riverbed look"
  • Usually due to extreme dryness.
• Flexural dermatitis
  • On insides of joints
  • Use low-dose steroids (well absorbed, thin skin)
• Nummular Dermatitis
  • Coin-shaped
• Perioral Dermatitis
  • Gets WORSE with steroid cream.
  • Treat with topical agent for rosacea.
  • Or rosacea antibiotics (tetracycline etc..)