Dermatitis Flashcards
What are the two main types of contact dermatitis?
irritant
allergic
What usually causes irritant contact dermatitis?
- common non-allergic reaction - due to weak acids or alkalis (e.g. detergents).
What is the cause of allergic contact dermatitis?
- Type IV hypersensitivity reaction.
- often seen on the head following hair dyes.
- Nickel Allergy
Where does irritant contact dermatitis normally present?
Hands
Main feature of irritant contact dermatitis?
Erythema
(crusting and vesicles are rare)
How does an allergic contact dermatitis normally present?
- Acute weeping eczema
Treatment of allergic contact dermatitis?
Topical potent steroids
Give an example of something which can cause both contact and irritant dermatitis?
Cement
- The alkaline may cause an irritant contact dermatitis
- the dichromates cause an allergic reaction
What is dermatitis artfacta?
psycho-dermatological condition characterised by self-inflicted skin lesions
Who normally presents with dermatitis artefacta?
Adolescent females
- strongly associated with personality disorder, dissociative disorders and eating disorders
Features of dermatitis artefacta
- linear/geometric lesions, well-demarcated from normal skin
- skin lesions “appear suddenly” e.g. overnight
- the lesions do not evolve over time
- multiple lesions at various stages of healing
- face (especially cheeks) and the dorsum of the hands most common
Mechanism of injuries in dermatitis artefacta
- scratching with fingernails or other objects
- burning skin with cigarettes
or chemicals (deodorant spray)
Management of dermatitis artefacta
- co-managed by dermatologists, psychologists and psychiatrists
- occlusive dressing
- topical antibiotics (if necessary) - bland emollient
- SSRI and CBT may be helpful
Dermatitis herpetiformis is associated with which other autoimmune disease?
coeliac
What autoimmune phenomenon causes dermatitis herpetiformis?
deposition of IgA in the dermis.
