Skin Path (Gomez)- Part 2 Flashcards
Acute Urticaria types
Hives
- Mast cell and IgE dependent
- - Acute allergic reaction (minutes) – medical emergency
- - Severe discomfort; profound itching - Mast cell dependent but IgE independent
- - Drug (#1) or other substance triggers mast cells directly (opiates, contrast media) - Mast cell and IgE independent
- - Aspirin induced vasodilation
- - Hereditary angioneurotic edema (C1-inhibitor deficiency)
** All types can cause fatalities
- Systemic anaphylaxis
- Laryngeal edema
- Rx- antihistamines, subcutaneous epinephrine and IM corticosteroids
(With known C1 inhibitor deficiency use C1 inhibitor (C1-INH) concentrates, kallikrein inhibitor or fresh-frozen plasma)
Acute Urticaria - what’s going on
Inciting agent may be known but * frequently inciting agent is not known
- Bee/wasp stings
- Allergic reaction drugs (penicillin, ASA, etc.)
Abrupt appearance of intensely pruritic * wheals +/- bullae
- Wheal: Transient edematous erythematous * plaque secondary to an acute allergic reaction
- Bullae: Larger fluid-filled lesions
Commonly involves trunk and extremities
Usually resolves 24 hrs.
- May persist days, even months
Eczema
=Spongiotic Dermatitis
- Intercellular epidermal edema and prominent lymphocytes in dermis and epidermis
Usually driven by T cell mediated * type IV hypersensitivity inflammation
Includes numerous pathologic and clinical conditions
Usually an acute onset of red, papulovesicular lesions (“boiling over” appearance) which may ooze or crust
Acute lesions may evolve into raised, scaling plaques
Erythema Multiforme
- Hypersensitivity (CD8+ cytotoxic T cells) reaction to
- Infections: * herpes simplex, * deep fungal (histoplasmosis), * Salmonella typhi, * leprosy
Drugs: * antibiotics, * salicylates, * anti-malarials
Malignancy
Collagen vascular disorders - “Multiforme” = wide variety of clinical appearances in addition to characteristic * “target” lesions (red-pale-red)
Pathophysiologically similar conditions
to Erythema multiforme
- Stevens-Johnson syndrome: Severe, systemic disease with atypical targetoid skin lesions that become bullous +/- oral and ocular involvement
- Toxic epidermal necrolysis: has diffuse necrosis and sloughing of skin and mucosae
Erythema Multiforme vs Urticaria
opposite; erythema has central blister/ necrosis surrounded by variable redness
urticaria has central clearing from edema
Psoriasis
Systemic disease causing a chronic skin condition
- Typical lesion: well-demarcated, pink to salmon plaque
- Involves elbows, knees, scalp, lumbosacral area, intergluteal cleft, and glans penis
- Koebner phenomenon – trauma can induce skin lesions
- Auspitz sign – scrape off scale and get punctate hemorrhages
- May involve nails
- Can involve other organs (e.g. psoriatic arthritis)
Lichen Simplex Chronicus
From chronic rubbing or scratching
If nodular = Prurigo nodularis
Seborrheic Dermatitis
Common chronic dermatitis (5% of population)
- Skin with high density of sebaceous glands
- Scalp, forehead, especially glabella (space between eyebrows), nasolabial folds, auditory canals, intergluteal fold
- Excessive dandruff on scalp common
Infection with superficial yeast (* Malassezia furfur) may play important role since condition is improved by use of topical antifungal agents
Lichen Planus
Self-limiting chronic inflammatory condition of * skin and oral mucous membranes
Multiple plaques that are symmetrically distributed, often on wrists and elbows and on the glans penis, *+ Koebner phenomenon
Usually resolves 1-2 years after onset, but may persist for years in oral cavity
Cutaneous Lupus Erythematosus (CLE)
- Localized cutaneous manifestations similar to those of systemic lupus erythematosus (SLE) but with * no SLE systemic manifestations
If only symptoms and signs are CLE then usually will not develop systemic symptoms and signs of SLE - 1/3 of all SLE patients will have cutaneous findings identical to those found in CLE (e.g. discoid lupus erythematosus)
- Major Cutaneous Findings: Excessive sun exposure may trigger cutaneous lesions or exacerbate them
- Malar erythema (also a characteristic of SLE)
- Chronic subtypes
– Discoid - coin-like scaling plaques
– Tumid – juicy red papules and plaques
– Lupus panniculitis/profundus – painful
subcutaneous nodules
what does lupus erythematosis look like?
Chronic plaques show thinned glistening (atrophic) epidermis & areas with dilated, tortuous dermal vessels
Note the central hypopigmentation surrounded by peripheral hyperpigmentation
microscopic: Granular deposits of antigen-antibody complexes and complement at
dermoepidermal junction constitute a positive “band test”
Rosacea
Fairly common in 30-60 y/o females Stages - Pre-rosacea (flushing) - Erythematotelengiectatic - Papulopustular * Phymatous
Pathophysiology uncertain
Numerous triggers
Perifollicular inflammation with changes similar to acne vulgaris microscopically
Blistering (Bullous) Diseases
common friction blister
imune-mediated
genetic-congenital
Common friction blister
Intraepidermal blister usually just beneath the stratum granulosum with scant or no inflammation in papillary dermis.
Immune-mediated blistering diseases
Pemphigus group of diseases
Bullous pemphigoid
Dermatitis herpetiformis
Genetic-congenital
blistering diseases
Epidermolysis bullosa- inherited defects in collagen, laminin, etc leading to several disorders with weak skin and blistering
Porphyrias
Blistering (Bullous) Diseases
Detachment sites and blister types
Detachment at:
Superficial desmosomes →
subcorneal blister
Deeper desmosomes →
suprabasal blister
Hemidesmosomes →
subepidermal blister
Blistering diseases: Adhesion Molecules Attacked
Attack at:
Superficial desmosomes Desmoglein 1 →
Pemphigus foliaceus
Deeper desmosomes
Desmogleins 1 & 3 →
pemphigus vulgaris
Hemidesmosomes BPAG1 and BPAG2 → Bullous pemphigoid or Reticulin in anchoring fibers→ Dermatitis herpetiformes
Pemphigus Group of Diseases
Autoimmune skin diseases
* IgG autoantibody to desmosomes of squamous epithelial cells
Five clinical and pathologic types
- Pemphigus vulgaris (80%): Involves mucosa and scalp, face, axilla, groin and other pressure points; classic bullous disease
- Pemphigus foliaceus: more benign course; involves face, scalp, chest and back and spares mucous membranes
Epidemic form occurs in South America (fogo salvagem)
- Pemphigus erythematosus: mild localized form of foliaceus which involves primarily malar area of face
- Pemphigus vegetans (rare): verrucous plaques instead of blisters involving axilla, groin, and flexural surfaces
- Paraneoplastic pemphigus: occurs with malignancies (lymphoma)
Pemphigus Foliaceus- what do we find?
Dsg1 in superficial desmosomes
more benign course; involves face, scalp, chest and back and spares mucous membranes
Pemphigus Vulgaris
- what we find
Dsg1 & Dsg3 in all desmosomes
Bullous Pemphigoid- what we find
BPAG1 & BPAG2 in hemidesmosomes
- Autoantibody to hemidesmosomes
- Subepidermal blister
- more resistant to rupture than pemphigus
Dermatitis Herpetiformis
IgA to gliadin attacks reticulin in dermal papillae fibrils
- Rare skin bullous disorder
M>F
Onset in 3rd and 4th decades - Major association with celiac disease (non-tropical sprue, gluten-sensitive enteropathy)
*- Anti-gliadin antibodies cross-react with reticulin in the anchoring fibrils in dermal papillae - Intensely pruritic plaques and vesicles
Extensor surfaces, elbows, knees, upper back and buttocks
Panniculitis
Inflammation of the subcutaneous fatty tissue
Septal
Lobular
- Erythema nodosum
Acute * septal panniculilits associated with infections (e.g. Beta-strep, TB), sarcoidosis, inflammatory bowel disease, malignancies and drugs (e.g. sulfonamides, oral contraceptives) - Erythema induratum
- Uncommon * lobular panniculitis and of unknown etiology (vasculitis?)
Weber-Christian disease - Idiopathic relapsing febrile nodular lobular panniculitis in children and adults
Factitial panniculitis - Self induced lobular panniculitis traumatic injury (injections)
Lupus may have a * lobular panniculitis (cutaneous lupus profundus/panniculitis)
Verruca Vulgaris
- Common in children and adolescents
Generally self-limited (6 months - 3 years) - Distinct, gray-white to tan 0.1 to 1.0 cm papules or plaques in skin
Due to * human papillomavirus (HPV)
Most commonly HPV subtypes 2 & 4 in cutaneous warts
Firm consistency, “cobble-stone” (roughed surface), firm to palpation
Characteristics determined by skin location:
- Verrucae plantaris (sole of foot) and * palmaris (palm of hand) tend to be elongated, broad and flat and larger 1-2 cm plaques
- Condyloma acuminatum of the anogenital region are 1 to 4 cm cauliflower-like growths and mainly contain HPV subtypes 6 & 11
Molluscum Contagiosum
Common self-limited viral disease caused by * poxvirus
Spread by direct contact
Primarily seen in young children and adults
0.2 -0.4 cm nodules on face, trunk and anogenital area
Acne Vulgaris
Life-long disease most despised during teenage years (zits)
* Chronic smoldering infection of the hair follicle by lipase producing * Propionibacterium acnes
Rx
- Retin-A - alters the chemical composition of the sebum of hair follicle so that P. acnes cannot thrive on sebum as a nutrient source
- Antibiotics - P. acnes eradicated (e.g. minocycline, a tetracycline that is incorporated into hair shaft)
Impetigo
Common superficial infection of skin
Highly contagious
Tends to occur predominately on hands and face
Two forms
* Impetigo contagiosa (non bullous)
* Impetigo bullosa
(differ predominately in the size of the pustule)
- Currently Staphylococcus aureus #1 in both subtypes
Bacterial toxins cleave desmoglein 1
Infection localized subjacent to stratum corneum
Honey-colored crust (highly infectious) - Historically beta-streptococcus in contagiosa or Staphylococcus aureus in bullosa
Treat with anti-bacterial soap and topical antibiotic (occasionally along with systemic antibiotics)
Superficial Fungal Skin Infections
Infections by * dermatophytes (Microsporum sp., Epidermophyton sp., Trichophyton sp. and Malassezia sp.) present in soil & on animals
Infection confined to the * stratum corneum of the epidermis
Dermatophytes grow in the keratin of the cornified layer
May have a mild inflammatory reaction to fungal products
- Predisposing conditions for skin infection
High moisture content of immediate skin environment
Lack of exposure to sunlight
Increased temperature of skin region
enclosed space such as shoes or groin
Use of communal shower or bathing facilities (athlete’s foot)
Tinea = Superficial Fungus Infections
- Tinea versicolor: Yeast infection by Malassezia sp.
Other tinea are by fungi producing yeast and hyphae and are named by location - Tinea capitis: scalp in children
- Tinea corporis (ringworm): trunk and extremities in all ages but more in children
- Tinea cruris: inguinal skin adjacent to genitalia
- Tinea pedis (athlete’s foot): feet between toes
- Tinea barbae: beard area in men
- Onychomycosis: fungal infection of nail beds
Arthropod Bites, Stings, Diseases
- Arthropods: invertebrate animals of the phylum Arthropoda (e.g. insects, spiders, crustaceans)
- Insects: arthropods with three-part body, three pairs of jointed legs, compound eyes and one pair of antennae (e.g. bedbugs, wasps, bees, flies and mosquitoes)
Injury to skin and/or other organ systems
Direct injury by insect part/secretions
1. Mosquitoes, chiggers, et.
- Acute or delayed hypersensitivity reaction
Bee/wasp stings, etc. - Direct toxin effect
Brown recluse spider, etc. - Vector for other disease transmission
Mosquitoes: malaria, West Nile virus, dengue, Zika virus, etc.
Ticks: Lyme disease, Rocky Mountain spotted fever, etc.
Infestations of Skin
: Parasites that are primarily localized to skin and skin appendages
ticks, chiggers/ mites, lice
Non-inflammatory Dermatoses
Ichthyosis vulgaris:
hyperkeratosis with “fish-scaling”; usually genetic abnormalities
Epidermolysis Bullosa: genetic abnormalities in structural proteins leading to massive bullae
Porphyrias:
usually autosomal dominant defects in heme synthesis leading to urticaria and subepidermal vesicles
Epidermolysis Bullosa
Epidermolysis bullosa: * genetic abnormalities in structural proteins leading to massive bullae
Simplex type: keratin 14 or 5 mutation
Intraepidermal (suprabasilar) blisters
Junctional type: defect at lamina lucida (laminin or BPAG2 defects)
Intra-lamina lucida subepidermal blisters
Patients have numerous complications from rupture of blisters (infections, disfigurement, adhesion of adjacent skin areas, etc.) and growth inhibition from increased energy needs to combat complications of disease
Porphyrias
Usually autosomal dominant * defects in heme synthesis
- congenital erythropoetic is recessive
Increased intermediates cause * urticaria and non-inflammatory * subepidermal vesicles - especially with sun exposure skin via light absorption by porphyrin ring
* PBG (porphobilinogen) in urine may become red or dark (+/- light exposure)
Acute neurovisceral with GI and neural symptoms
- Acute intermittent
- Aminolevulinic acid dehydratase deficient
Acute neurovisceral with cutaneous problems
- Variegate (protoporphyrogen oxidase)
- Hereditary coproporphyria
Non-acute (cutaneous with light induced lesions)
Congenital erythropoetic (uroporphyrinogen III synthase)
Erythropoetic (=erythrohepatic protoporphyria) (ferrochelatase)
X-linked protoporphyria (over-activity of amino-levulinic acid synthase)
Cutanea tarda (uroporphyrogen III decarboxylase)
- Associated with hypertrichosis
