lichen planus and lichenoid reactions Flashcards
what is the definition of lichen planus?
> a clinically distinctive macupapular mucocutaneous rash with a characteristic distribution
itchy when affecting skin with a tendency to develop at sites of trauma
eventually heals without scar but may leave hyperpigmented macules
what is lichen planus like on the skin?
> violaceous papule topped with a silver scale
flexor aspect of wrists, forearms, ankles and also torso
wickhams striae present
oral and skin lichen planus have many Similarities but are not the same
what is a lichenoid reaction?
> something that resembles lichen planus clinically and histologically but is caused by an identifiable agent eg. a drug
what are the general features of LP?
affects around 2% of the population -
> half of those with skin LP have oral lesions
> not everyone with oral lesions have skin LP
> females more than males
rare in children generally older (40+) age group
what is the aetiology of oral LP?
UNKNOWN
what are the proposed aetiological factors?
> infective organ (viruses)
stress
autoimmunity
drug therapy
restorative material
idiopathic
when do you call LP a LR?
if you can determine that the changes are due to drug therapy, restorative materials or other triggers
what do you call a LR caused by a restorative agent?
> contact lesion
what is Idiopathic lichen planus?
> if you can’t determine that the changes are due to drug therapy, restorative materials or other triggers
(in a proportion of patients, careful analysis revealed possible causative agents the elimination of which is followed by healing of the lesions
what is the difference between LP and LR?
> develops 3 weeks after change in antihypertensive medication (= LR)
resolves when old amalgams replaced by composite (= LR)
no fillings, no drugs, PMH NAD (=LP)
what is the onset of LP and LR?
onset = spontaneous or related to any event?
what is the duration of LP and LR?
> duration = chronic, years rather than months
what is the number of LP and LR?
> number = usually multiple
what is the frequency of LP and LR?
> frequency = persistent, perhaps with episodic exacerbations
what are the sites of LP and Lr?
> sites = almost anywhere in the month , bilateral or unilateral?
