Lichenoid Disorders Flashcards
What is meant by a lichenoid disorder?
clinically - shiny flat topped itchy papular rash
histologically - band like inflammatory infiltrate in the upper dermis with basal cell necrosis
Name four lichenoid disorders
- lichen planus
- drug eruptions
- graft vs host disease
- pityriasis lichenoides
What is the name given to the appearance of basal cell necrosis?
Civatte bodies
Describe the aetiology of Lichen Planus
Genetic association & links to hepatitis C, T cell mediated autoimmune inflammatory condition
Describe the histological appearance of lichen planus
Acanthosis (irregular saw tooth thickening of epidermis) civatte bodies with lymphocytic infiltrate
Name the different types of lichen planus
Hypertrophic
Atrophic
Follicular
Mucosal
How does lichen planus present?
Shiny flat topped violaceous polygonal papules often very itchy
What is the name for the white lines with a lace like patten on surface of papules and bullae?
Wickham’s striae
How is Lichen Planus managed?
Can clear spontaneously but treatment is symptomatic and potent topical steroids. If unresponsive systemic therapies may be required.
What are the four types of immune mediated reactions?
I - anaphylactic
II - cytotoxic reactions
III - immune complex mediated
IV - cell mediated delayed
For each of the immune mediated reactions what is the typical corresponding dermatological presentation?
I - Urticaria
II - Pemphigus and Pemphigoid
III - Purpura/rash
IV - erythema/rash
Name the risk factors for a drug eruption
- age
- gender
- genetics
- concomitant disease (virus/CF)
- immune status
- drugs
What is the most common type of drug eruption?
Exanthematous type 4 hypersensitivity reaction
How does exanthematous type 4 hypersensitivity reaction present?
Widespread symmetrical rash with no mucosal involvement can be itchy but often associated with a mild fever, 4-21 days after taking first dose
What are the indications of a severe exanthematous reaction?
- mucous/fascial involvement or oedema
- confluent erythema
- SOB/Wheeze/Lymphadenopathy
- Blisters, purpura, necrosis
What antibiotics can cause an exanthematous reaction?
SEPS sulphonamides erythromycin penicillin streptomycin
What anti-epileptic drugs can cause an exanthematous reaction?
Carbamazepine
Phenytoin