Skin Flashcards
Macule:
flat, circumscribed area <5 mm • Patch: flat, circumscribed area >5mm
• Papule:
elevated lesion <5 mm
- Plaque: elevated lesion > 5 mm
* Pustule:
discrete pus-filled lesion •
Vesicle:
fluid-filled lesion <5 mm •
Bulla:
fluid-filled lesion >5 mm
Urticaria: Hives
CLINICAL FEATURES
• Erythematous, edematous, and pruritic papules and plaques (wheals)
• Individual hives last <24 hours (just a few hours), but episodes can continue for weeks
• Localized or generalized
Acute Urticaria PATHOGENESIS
Mast cell degranulation
increased dermal vascular permeability
dermal edema
• Immediate Type I (IgE) hypersensitivity rxn
• Inciting factor: medications (opiates, abx)
Acute Urticaria treatment
TREATMENT
• Antihistamines
Acute Eczema CLINICAL FEATURES
- Pruritic inflammatory erythematous papules and scaly plaques
- Can become vesicular and crusted
- over time, skin thickens due to acanthosis
- Spongiotic dermatitis on histo: epidermal edema, perivascular lymphocytic infiltrate, and mast cell degranulation
Types of Eczema
Atopic :
• Allergic contact:
• Photoeczematous:
Irritant dermatitis
Eczema
Atopic :
autoimmune related
– Genetic predisposition
– Atopic triad of asthma, allergies, and eczema – More common in childhood, outgrow as adult
Eczema
• Allergic contact:
contact exposure to an allergen
– Type IV hypersensitivity rxn: CD4+T lymphocyte mediated – Poison ivy, neosporin
Eczema
• Photoeczematous:
abnl reaction to ultraviolet light •
Eczema
Irritant dermatitis:
contact exposure to irritant
Erythema Multiforme
Hypersensitivity reaction most often due to medication/drug and certain infections
•
– Common meds: sulfonamides, PCN, NSAIDs, hydroquinone
– Infections: HSV and mycoplasma
On spectrum of Stevens Johnson (more mucosal involvement and wider surface area) and toxic epidermal necrolysis (TEN- full thickness epidermal necrosis)
Erythema Multiforme
CLINICAL FEATURES
- “targetoid” lesions
- Multiple features with macules, papules, vesicles with central pallor
- Can lead to epidermal desquamation if progresses
Chronic Inflammatory Dermatosis: PSORIASIS
• Chronic inflammatory dermatosis in
1-2% of US population
Chronic Inflammatory Dermatosis: PSORIASIS
• Associated with
heart disease and 10% can develop psoriatic arthritis
Chronic Inflammatory Dermatosis: PSORIASIS
————- mediated rxn
• Autoimmune, T-cell
Chronic Inflammatory Dermatosis: PSORIASIS
• Can be localized to
specific areas or generalized and severe (erythroderma)
Chronic Inflammatory Dermatosis: PSORIASIS
CLINICAL FEATURES
• erythematous salmon-pink colored plaques with silvery scale
– extensor elbows, knees, scalp, gluteal cleft
– nail thickening and dystrophy
• Koebner: induce lesion by local trauma
• Auspitz sign: punctate bleeding when overlying scale is removed
Psoriasis Histopathology:
• Epidermal thickening (acanthosis) with incr epidermal cell turnover but lack of maturation
– Epidermal hyperplasia
– Downward extension of rete ridges
– Parakeratotic scale
Chronic Inflammatory Dermatosis: Lichen Planus
- Pruritic
- Purple
- Polygonal
- Planar papules and plaques
- Covered in Oral Pathology
Infectious Dermatoses
Bacterial Infection • Impetigo
– ———-, can be Strep pyogenes
Staph Aureus
Infectious Dermatoses
Bacterial Infection • Impetigo
– Contagious, more commonly
in kids, spread through direct contact
Infectious Dermatoses
Bacterial Infection • Impetigo
– Starts as small
macule often perioral/perinasal