Eczema/Dermatitis Flashcards
What is eczema?
Synonymous with dermatitis - presents as poorly demarcated, itchy rash caused by a break down in the barrier function of the skin.
What is the pathology of eczema?
Characterised by inflammation and spongiosis
Earliest histological change in eczema is swelling within the epidermis. This swelling is due to separation of the keratinocytes by fluid accumulating between them, and this appearance is known as spongiosis. Later, there may be hyperkeratosis (an increase in the thickness of the stratum corneum) and parakeratosis (retention of nuclei in the stratum corneum), which give rise to the clinical scales.
In severe cases, the intercellular oedema can then join up to form foci of fluid within the epidermis, recognised clinically as blisters or vesicles (pompholyx)
What is meant histologically by the term eczematous changes?
Refers to a collection of fluid in the epidermis between the keratinocytes (‘spongiosis’) and an upper dermal perivascular infiltrate of lymphohistiocytic cells. In more chronic disease there is marked thickening of the epidermis (‘acanthosis’)
What are risk factors for the development of eczema?
Multifactorial
- History of atopy
- Genetic
What are the different types of endogenous eczema?
- Atopic
- Discoid
- Hand
- Seborrhoeic
- Venous
- Asteatotic
What are the types of exogenously caused eczema?
- Contact - allergic/irritant
- Photosensitive
- Lichen simplex/nodular prurigo
What are features of atopic eczema?
Typically flexor surfaces, around eyes, and on the neck
- Erythematous rash
- Scaly patches
- Acute lesions - weepy, small vesicles
-
Pruritis - Worse with dry air, sweating, local irritation, stress
- Causes excoriation and lichenification
What are complications of atopic eczema?
- Infection - staph aureus, strep, HSV, molluscum, HPV
- Conjunctival irritation
- Keratoconjunctivitis
- Cataract
In someone with eczema, what might the following be?
Eczema herpeticum
How would you investigate someone with suspected atopic eczema?
Clinical diagnosis
- Consider RAST/patch testing
How would you manage the following?
Eczema herpeticum - Admit and IV aciclovir
What are triggers of atopic eczema?
- Irritants
- Infections
- Inhalants
- Ingestion of substances/foods
Wha tproportion of children with atopic eczema will spontaneously improve before their teenage years?
80-90%
How would you manage atopic eczema?
- General measures - Avoidance of irritants/allergens, frequent emollients, bath soap/oil substitute
- Topical therapies - steroids for flare ups, immunomodulators as steroid sparing agents
- Oral therapies- oral antibiotics/antivirals, sedating antihistamines
- Phototherapy
- Systemic immunosuppressive therapy - oral prednisolone, ciclosporin
What irritants would you advise people to avoid if they had atopic eczema?
- Soaps
- Furry animals
- Cotton clothing
- Getting overly hot
What is regarded as the triple combination therapy of topical therapies?
- Topical steroids
- Frequent emmollients and bath oil
- Soap substitute
What is the function of emmolients?
Treat dryness and act as a barrier
How often should those using emollients use them?
At least twice a day
In someone with eczema, what is the following?
Lichenificaiton
What are featres of hand eczema?
- Itchy vesicles or blisters on the palm and along the sides of the fingers
- Diffuse erythematous scaling and hyperkeratosis of the palms
- Scaling and peeling, most marked at the finger tips
What are featuers of seborrhoeic eczema in neonates?
Affects sites rich in sebaceous gland:
- Yellow thick crust on the scalp (cradle cap)
- More widespread erythematous, scaly rash can be seen over the trunk, especially affecting the nappy area
- Little associated pruritis
What are features of seborrhoeic eczema in adults?
Affects areas rich in sebaceous glands
- Erythematous scaling - sides of the nose, in the eyebrows, around the eyes and extending into the scalp
- Marked dandruff
- Blepharitis may be present.
What are features of venous eczema?
Occurs on legs due to chronic venous ulceration:
- Haemosiderin deposition
- Venous leg ulcer
- Lesions around lower leg
What might the following be?
Contact/irritant eczema
What type of hypersensitivity reaction is often implicated in the following?
Type IV hypersensitivity - not always; can just be irritation
What are features of lichen simplex?
Common sites - nape of neck, lateral calves, upper thighs, upper back, scrotum/vulva
- Thickened, scaly and hyperpigmented areas of lichenification
What are features of nodular prurigo?
Esp. on upper trunk and extensor surfaces of the limbs
- Individual, itchy papules
- Domed nodules appear
- Significant excoriation over lesions
What is the following?
Asteatotic eczema - dry plate-like cracking of the skin with a red, eczematous component, which occurs in elderly people. It occurs predominantly on the lower legs and the backs of the hands, especially in winter.
