lichen planus and lichenoid reactions Flashcards
(27 cards)
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?
what is the systemic upset of LP and LR?
systemic upset - none (minority have involvement of other mucosal or cutaneous sites)
what are the presenting pathways of LP and LR?
> asymptomatic
discomfort/ pain on eating
change in texture of mucosa
ulceration
what is the variety of clinical patterns LP/ LR can appear as?
> reticular
papular
plaque
atrophic
erosive
bullous
(you can have different patterns on the same patient)
what are the most common sites of distribution?
> buccal mucosa
lateral border of tongue
dorsum of the tongue
attached gingiva
what are the least common sites of LP/LR
> palate
floor of mouth
edentulous alveolar mucosa
what are the other sites affected by LP/LR?
> skin
Nails
genitalia
ears (tympanic membrane
conjunctiva
oesophagus
histopathology of LP/ LR ?
> epithelium may be hyperkeratonic, hyperplastic, atrophic or ulcerated
basal cell layer exhibits “liquefaction degeneration” (apoptosis, civatte bodies)
band like infiltrate of T Lympocytes hugging the interface, many lymphocytes trafficking through the epithelium
interface mucositis (umbrella term)
what is the proposed pathogenesis of LP/ LR ?
- something alters the protein signature of the basal keratinocyte
- langerhans cells detect the new antigen
- antigen presented to T cells
- cell mediated immunity develops
- T cells infiltrate back to the altered epithelium and kill individual basal cells
- the epithelium reacts in the only way it knows
what conditions mimic LP/LR?
> frictional keratosis
lupus erythematous
tobacco-related keratosis
potentially malignant oral lesion
graft versus- host disease
