7: Dermatitis / atopic eczema Flashcards
What is another name for dermatitis?
Eczema
What is another name for eczema?
Dermatitis
What is papillomatosis?
Irregular epithelial thickening
What is the characteristic histological feature of eczema?
Spongiosis (oedema between keratinocytes)
Which immune cells infiltrate the epidermis in eczema?
Neutrophils
Lymphocytes
What is the common symptom for all types of eczema?
Pruritus (itching)
What are the two phases of an eczema reaction?
Acute phase
Chronic phase
What happens in the acute phase of an eczema reaction?
Rapid acute inflammation
What does eczema look like in the acute phase?
Papulovesicular
Erythematous
Spongiotic
Oozing / scaly / crusty
What does eczema look like in the chronic phase?
Thickened (lichenification)
Elevated patches –> PLAQUES
Even scalier
What are the four defining morphological features of eczema?
Itchy
Ill-defined
Erythematous
Scaly
What type of eczema is brought about by a Type IV hypersensitivity reaction?
Contact allergic eczema
What type of eczema reaction is brought about by substances which aren’t allergens?
Contact irritant eczema
Give two examples of substances which cause contact irritant eczema.
Soap
Water
Urine
Faeces
What is atopic eczema?
Inflammation of the skin due to genetic and environmental factors versus allergens or irritants
Which types of hypersensitivity reactions occur in drug-related eczema?
Type I
Type IV
Which immune cells are seen in drug-related eczema?
Eosinophils
What is the histological feature common to ALL types of eczema?
Spongiosis (oedema between keratinocytes)
If a patient has eczema on sun-exposed areas only, which type of eczema may they have?
Photosensitive eczema
What is lichen simplex eczema?
Inflammation due to scratching
What is stasis dermatitis?
Skin inflammation due to hydrostatic pressure in legs with poor circulation (see also: varicose veins)
Which cells leak into the extracellular compartment and cause inflammation in stasis dermatitis?
Why?
Red blood cells
Increase in capillary hydrostatic pressure (in turn due to decreased venous circulation, e.g heart failure or peripheral vascular disease)
Give some examples of allergens which cause contact allergic dermatitis.
Chemicals
Drugs (e.g penicillin)
Nickel!!!!
Where is nickel commonly found which can cause contact allergic dermatitis?
Belt buckles, buttons
Why do people tend to get worse contact allergic reactions on the dorsal surfaces of their hands?
The skin is thinner
Which substance, increasingly found in the air, can cause contact allergic reactions on the face?
Perfume
What is typically seen in the acute phase of eczema?
Weeping blisters (due to rapid severe spongiosis)