DD 03-05-14 09-10am Inflammatory Skin Disorders - Dunnick Flashcards
Dermatitis defn.
= Inflammation of the skin
= commonly used by dermatologists to refer to spongiotic dermatitis, a nonspecific reaction pattern
seen on skin biopsy
Atopic Dermatitis - epidemiology (age, prevalence)
Common skin disease which may begin at any age, however a majority begin before age 5.
Prevalence: 7-17.2% in children
Atopic Diathesis
= aka what predisposes one to atopic dermatitis
- Asthma
- Allergic rhinitis
- Atopic dermatitis
Atopic Dermatitis - Diagnostic Criteria
Must have: Itchy skin, plus…
3 more of the following:
- Hx of skin crease involvement (or face if < 10 yrs)
- Personal Hx of asthma or hay fever (or FHx of atopic disease if pt < 4 yrs)
- Hx of dry skin w/in last year
- Visible flexural eczema (or face if pt < 4 yrs)
- Onset under 2 years of age
Atopic Dermatitis - Pathogenesis
- Barrier disrupted skin
- Filaggrin mutation
- Staphlyococcus aureus (acts as a superantigen)
- Elevated IgE
- Eosinophilia
- TH2 type cytokine (IL-4, IL-5, IL-10) immune response produced
Atopic Dermatitis - Infantile manifestations
From birth to 2yrs
Dry, red scaly areas confined to the cheeks
—> Becomes flushed with exposure to cold
Some have more generalized eruption, characterized by:
- erythematous papules
- redness
- scaling
- areas of lichenification
Atopic Dermatitis - Childhood manifestations
From 2-12 yo
Characteristic involvement of flexural skin:
- Antecubital fossa
- Popliteal fossa
- Neck
- Wrists
- Ankles
Atopic Dermatitis - Adult manifestations
From 12 yo to adult
Eyelid dermatitis
Hand dermatitis
Atopic Dermatitis - Associated Features
- Dry Skin (Xerosis)
- Keratosis Pilaris
- Ichthyosis vulgaris
- Hyperlinearity of the palms
Eczema
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Eczema
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Eczema
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Eczema
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Eczema
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Irritant Contact Dermatitis - basics
= Non-immunologically mediated rxn resulting from direct cytotoxic effect
- Either from a single or repeated exposure to the
irritant
- No specific “test” for irritant dermatitis
= Most common type of contact dermatitis
Irritant Contact Dermatitis - types of irritants
Strong vs. Weak Irritants
Strong irritants:
- damage skin directly even in small amounts contacting skin for a short time
- i.e. strong acids & bases
- generally carry warning labels & often suggest skin protection such as gloves be used
Weak irritants:
- “harmless” by themselves
- frequent, repeated contact may damage skin
Examples of Weak Irritants
- Soap and water
- Skin products (even “baby” and “hypoallergenic”)
- Perfumes
- Wool
- Raw Foods (meat, fruits, or vegetables held while
preparing foods) - Body Secretions (feces, urine, saliva, sweat)
- Friction
Allergic Contact Dermatitis
- Requires contact exposure of an allergen,
immune response & development of “memory” T cells - Type IV, delayed-type hypersensitivity rxn usually starts 24-48 hours after allergen exposure, but it can be delayed longer
What is contact allergy?
Delayed type hypersensitivity reaction
Allergens
= small chemical molecules (haptens)
= usually < 500 Daltons
- Small size allows penetration through skin
- presented by Langerhans cells to T cells
- mostly weak allergens that require repeat exposures prior to sensitization
Elicitation of ACD by allergens
Caused by inflammatory cytokines including TNFα and IL-1
What is a patch test?
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When do you patch test?
= gold standard test for diagnosing ACD Use with... - Pts w/ suggestive Hx - Pts w/ resistant dermatitis - Chronic dermatitis - Occupationally-related dermatitis - Atopic eczema - flaring - Stasis dermatitis - Photo or airborne distribution
patch test or allergic contant dermatits
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patch test or allergic contant dermatits
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Risk Factors for Nickel Sensitivity
Female sex (RR 3.74 women to men)
Younger age (RR 3.23 Age 30 or less)
- 12.9% nickel positivity in Denver children < 5 yr (54% boys & 45% girls)
- 30.4% nickel positivity (UCH Age < 18 years)
Ear piercing
- 14.8% with ears pierced: 1.8% without
(567 Danish patients nickel positivity)
Classic example of nickel allergic contact dermatitis
- in periumbilical area in an 11 yo, from button on pants (use duct tape as a physical barrier to prevent)
Prevalence of positive patch tests for nickel
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Prevention of nickle ACD
1994 European Union Nickel Directive
—> Limits amount to no more than 0.05% nickel content in posts used for body piercings.
—> Limits amount released from objects in direct & prolonged contact w/ skin to no more than 0.5 mg
nickel/cm2/week
—> Mandates that these objects, such as jewelry, watches, buttons, & zippers, shall maintain this requirement for 2 years of normal use
Regulation of nickel - affects
= has successfully lowered rates of nickel sensitization in Europe
- In Germany, nickel allergy in women under
age 30 decreased from 36.7% (in 1992) to 25.8% (in 2001)
- In Denmark, nickel sensitivity in children under age 18 fell from 24.8% to 9.2% from 1985–1986 to 1997–1998
ACD
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ACD
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ACD
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Fragrance as allergens
- > 2,800 fragrance ingredients
- > 100 of these are known contact allergens
- Botanicals are also used as fragrance & can cause contact allergy
- Unscented products may have a masking fragrance, therefore pts w/ fragrance allergy should use only fragrance-free products
Fragrance - laws
- Companies are reluctant to disclose fragrance components
- EU requires labeling of 26 fragrance allergens on products if concentration >100 ppm for a rinse-off product & > 10 ppm for a leave-on product
- FDA bans ~10 chemicals used in fragrances & does not actively regulate this industry
Formaldehyde Releasing Preservatives
Formaldehyde
- 8.4% Prevalence, 71.5% Prevalence
Quaternium-15
- preservative that most frequently causes ACD in the US
- 9.3% Prevalence, 88.4% Relevance
2-Bromo-2-nitropropane-1, 3-diol
Diazolidinyl urea
DMDM Hydantoin
Imidazolidinyl urea
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Bacitracin and Neomycin
- Neomycin & bacitracin allergies often occur together (co-sensitization)
- Wide spread use has led to increase sensitization
Co-sensitization defn.
= allergy to 2 allergens which are not structurally related, but are frequently used concomitantly
Stasis Dermatitis - associations
Often seen in association with other signs of venous insufficiency of the lower extremities:
- Varicose veins
- Chronic lower extremity edema
- Venous stasis ulcers
- Lipodermatosclerosis
Stasis Dermatitis - Complicating Factors
- Dryness
- Itching
- Allergic contact dermatitis due to use of topical preparations (i.e. topical antibiotics)
- Irritant Dermatitis due to wound exudates
Stasis Dermatitis - treatment
- Compression
- Elevation
- Exercise calf muscles
- Vascular surgery
- Topical steroids
- Avoid allergens
Lichen Simplex Chronicus defn.
= Thick, scaly plaques with “lichenification” that result from chronic rubbing and scratching
Lichen Simplex Chronicus - treatment
- Topical steroids are first line therapy
- Antihistamines can be used for itching
- Pts need to be counseled to break the itch-scratch cycle
Venous Stasis Ulcers - seen commonly w/…
- Common in pts w/Hx of leg swelling, varicose veins or blood clots
Venous Stasis Ulcers - appearance / location
- Primarily found on medial lower leg just above
the ankle - Red in color with yellow fibrinous base
- Borders irregularly shaped
- May be purulent if infected
Nummular Dermatitis - aka, main demographic
- aka Discoid Eczema
- More common in men age 50+
Nummular Dermatitis - location / appearance
- Most often occurs on legs, but can appear on arms and trunk
- Patches may be red, scaly & become crusty
- Tends to be stubborn
Nummular Dermatitis - treatment
First line therapies:
- Moisturization
- Minimization of soap
- Topical corticosteroids
Cellulitis vs. Erysipelas vs. Dermatitis - Morphology
Cellulitis
- warm, tender, erythematous
- patches or plaques
Erysipelas
- warm, tender, erythematous
- sharply demarcated, raised plaque
Dermatitis
- erythematous papules
- thin plaques w/scale
Cellulitis vs. Erysipelas vs. Dermatitis - Location of Inflammation
Cellulitis
- dermis & subQ tissue
Erysipelas
- dermis & minimal subQ tissue
Dermatitis
- epidermis & dermis
Cradle Cap (Seborrheic dermatitis)
= Flaky, white to yellowish oily scale on scalp
- Can become confluent w/ thick scale covering most of scalp
- Begins 1 wk after birth & may persist for several months
Seborrheic Dermatitis - appearance / location
- Facial involvement is usually symmetric over
medial eyebrows, nasolabial folds & ears - Occurs in areas rich in sebaceous glands (scalp, face, ears, chest)
- Characterized by flaky, “greasy” scales
Seborrheic Dermatitis - Pathogenesis
Thought to be due to combo of…
- overproduction of skin
- irritation from yeast (Malassezia furfur)
Linked to:
- Neurologic conditions, including Parkinson’s disease, head injury, and stroke
- HIV
Seborrheic Dermatitis
“Dandruff”
= Commonly involves scalp
- more diffuse lesions w/ finer scale than psoriasis
Psoriasis
- Affects up to 2% of population
- Positive FHx in 36% of psoriasis pts
- Impacts quality of life
Histology of Psoriasis
Shows
- hyperproliferation of the epidermis
- elongation of the rete ridges
- neutrophils
- dilated capillary loops in dermal papillae
Psoriasis - Clinical Subtypes
- Chronic Plaque Disease
- Guttate
- Erythroderma
- Pustular Psoriasis
Psoriasis - Chronic Plaque Disease
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Guttate Psoriasis associated with Strep Throat
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Psoriasis - Palmar/Plantar
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Psoriatic Arthritis
Occurs in 5-20% patients
Psoriasis Affects Quality of Life
- Impacts public perceptions
- Negatively impacts interactions at home & work
- Interferes with sleep, sexual activity, walking
and using hands
Psoriasis and Comorbidities
Persistent low grade inflammation favors development of:
- insulin resistance
- obesity
- metabolic syndrome
Metabolic syndrome pts have accelerated atherosclerosis due to inflammation
Psoriasis is an independent risk factor for
Cardiovascular Disease
Pts in their 40s with…
- severe psoriasis double their risk for MI
- mild psoriasis RR increases by 20%
Psoriasis - Treatment of Localized Disease
- Calcipotriol (Vit D3 analog)
- Corticosteroids
- Topical Retinoids
- Phototherapy
- UVB/NBUVB
- PUVA
Psoriasis - Treatment of Widespread Disease (+/- Psoriatic Arthritis)
- Methotrexate
- Cyclosporin
- Systemic Retinoids
- Biologics
- – Anti-T lymphocyte
- – Anti-TNF alpha
Stasis dermatitis location
lower legs
Seborrheic dermatitis location
scalp
Atopic dermatitis location
flexor surfaces
Psoriasis location
extensor surfaces
may include arthritis
Stasis dermatitis etiology
lower extremity edema
Seborrheic dermatitis etiology
Malassezia furfur (yeast)
Atopic dermatitis etiology
Filaggrin
Irritant dermatitis etiology
common irritants
Allergic contact dermatitis etiology
common allergens
Atopic dermatitis - Misc. Facts to Know
Associated with Asthma and Allergic rhinitis
Allergic contact dermatitis - Misc. Facts to Know
- Delayed type hypersensitivity reaction (Type IV)
- Dx confirmed with patch testing
Psoriasis - - Misc. Facts to Know
May be associated with increased risk
of cardiovascular disease
