Dermatitis/ eczema Flashcards
Define the following terms in skin pathology: a) hyperkeratosis b) parakeratosis c) acanthosis d) papillomatosis e) spongiosis
a) increased keratin layer thickness b) persistence of nuclei in keratin layer c) increased epidermal thickness d) irregular epithelial thickening e) oedema between keratinocytes
How does the acute phase of eczema/dermatitis present?
Il-defined papulovesicular lesions, red, itchy, oozing
How does the chronic phase of dermatitis present?
Thickened, elevated plaques, scaly
How do the various sub-types of dermatitis/eczema differ?
Different pathogenetic mechanisms
What is this lesion most likely a result of?
Contact allergic dermatitis in response to nickel
Briefly describe the immunopathology of contact allergic dermatitis.
Delayed Type (IV) hypersensitivity
Sensitisation and elicitation phases
Antigen presentation to T cells in lymph nodes
On subsequent antigen challenge sensitised T cells migrate to skin and instigate allergic reaction
Other than allergic contact dermatitis, what other form of dermatitis can be related to occupation?
Irritant contact dermatitis- non specific physical irritation
Can overlap with allergic and be difficult to distinguish
What are the main features of atopic eczema?
Prurutis
Ill-defined erythema and scaling
Dry skin
Flexural distribution
Association with other atopic conditions
What does “crusting” of areas of eczema indicate?
Staph aureus infection
How are these lesions described and what is the likely diagnosis?
“monomorphic punched-out lesions”
Eczema herpeticum
Mutations in which gene predipose to eczema? What is the mechanism of this?
Fillagrin
Compromised skin barrier function
Roughly what proportion of school age children does eczema affect?
25%
How is eczema treated?
Emollients
Corticosteroids (of appropriate strength for severity of symptoms)
Avoidance of irritants
Antibiotics for secondary infection (topical)
Severe refractory- phototherapy, systemic steroids, immunosuppressants
Discoid eczema
What is the diagnosis and underlying pathophysiology?
Stasis eczema
Increased hydrostatic pressure, oedema, red cell extravasation leading to irritation of the skin
Seborrhoeic dermatitis
