Eczemas and Allergic Skin Diseases 1 Flashcards
Irritant
offending agent that is toxic to the skin and produces inflammation in all patients; limited to area of exposure
Allergen
offending agent that produces reaction in some patients; reaction may spread beyond site
Hypersensitivity
local or generalized reaction following contact with specific allergen
Immediate hypersensitivity response
appears within minutes of exposure, IgE mediated; type 1 reaction (uticaria, anaphylaxis, drug/food allergy)
Delayed hypersensitivity response
appears 48-72 hours after exposure; indicated cell-mediated (T cells) response; Type IV (4) (contact dermatitis, tuberculin skin test)
Cytotoxic Antibody IgG/IgM
Type II - transfusion rx, Rh incompatibility
Immune complex reaction
Type III - Lupus, Polyarteritis nodosa
Irritant Contact Dermatitis (ICD)
disruption of skin barrier through mechanical or chemical exposure; localized (type 1)
Common ICD irritants
soaps, detergents, cement, petroleum, acetone, fiberglass, wool
Acute ICD
single exposure damaging keratinocytes- painful sensation, burning
blistering-> erosion-> crusting-> scaling-> necrosis-> shedding-> ulceration->healing
Chronic ICD
most common; painful burning and itching, seen on hands exposed to wet work
chapping->hyperkeratosis with scaling->fissures and crusting
Management of ICD
use gloves, remove irritant, use Burrow’s solution for burning, apply emollients (petroleum jelly/creams), severe acute cases benefit from oral glucocorticoids
Allergic Contact Dermatitis (ACD)
re-exposure to a substance a person is sensitized to; can remain confined to site or in strong sensitization may spread. EX allergans-creams, nickel, makeup, plants
erythema->papules->vesicles->erosions->crusts->scaling
*papules are often indicative of ACD and not usually seen in ICD
Management of ACD
Burrow’s solution, topical steroids (ointments preferred)
If severe use oral prednisone (start on high dose and taper down 2-3 wks)
Allergic Phytodermatitis
ACD (Allergic Contact Dermatitis) due to plants. ex- poison ivy, poison oak and poison sumac
contaminated skin should be washed within 30 minutes to get rid of the oleoresin (oil)
Atopic Dermatitis
“Eczema” itchy dry skin
inflammation of the skin on face and flexor surfaces
often in infancy or early childhood
may be seen as a triad with asthma and rhinitis
mixed type I and IV
Atopic means
hereditary tendency towards allergic reactions
Atopic Dermatitis management
Usually diminishes as child grows, 10% lifelong persistance
prevent from rubbing and scratching is essential
use emollients/moisturizers
can use prick test or RAST to identify food allergy causing it
can use topical calcineurin inhibitor (off label for less than 2 with good results)
can use crisaborale 2% ointment
severe cases can use both
**a balanced approach to long term management is recommended
Lichen Simplex Chronicus
a chronic patch from repetitive rubbing or scratching
occurs in adults, many have a history of atopic dermatitis (AD)
may appear as confluence of papules or solid plaque
Lichen Simplex Chronicus management
Stop rubbing or scratching
topical steroids under an occlusive dressing
antihistamines at night to prevent scratching
Dyshidrosis (Dyshidrotic Eczematous Dermatitis, DED)
A type of vesicular eczema; most commonly characterized by vesicles on dorsum of the hand
Exacerbating factors may exist friction, cold, excessive exposure to water
Dyshidrosis management
Topical steroids with occlusive dressing
Nummular Eczema
A type of eczema with a characteristic coin shape
on forearms and calves, rare in children
treatment is moisturizers and topical steroids
Pityriasis Alba
A mild type of atopic dermatitis, presents as hypo pigmented macules on the face and neck pf preadolescent
triggered by sun exposure, bathing, heat
avoid triggers, topical steroids
