Lichen Planus

Question 1

Definition of lichen planus

Answer 1

Inflammatory disorder with manifestations
on the skin, genital and oral mucous membranes. More rarely it affects the lacrimal duct,
oesophagus and external auditory meatus. It is an
inflammatory condition of unknown pathogenesis but
it is probably an immunological response by T cells. Weak circulating basement membrane zone antibodies have been shown to be present in 61% of patients with erosive lichen planus of the vulva. In some cases, there is overlap between LS and lichen planus.

Question 2

Symptoms of lichen planus

Answer 2

. Itch/irritation
. Soreness
. Dyspareunia
. Urinary symptoms
. Vaginal discharge
. Can be asymptomatic
- It can be anywhere on the body
- Mucosal surfaces, more common in the mouth
- More pain than itch

Question 3

Signs of lichen planus: classical

Answer 3

Typical papules will be found on the keratinised
anogenital skin, with or without striae on the
inner aspect of the vulva. Hyperpigmentation frequently follows their resolution, particularly those with dark skin. This type of lichen planus may be asymptomatic

Question 4

Signs of lichen planus: hyperthrophic

Answer 4

These lesions are relatively rare and
can be difficult to diagnose. They particularly affect
the perineum and perianal area, presenting as thickened warty plaques which may become ulcerated,
infected and painful. Because of these features,
they can mimic malignancy. They do not appear to
be accompanied by vaginal lesions
- Well demarcated glazed erythema around introitus

Question 5

Signs of lichen planus: erosive

Answer 5

The most common subtype to cause vulval
symptoms. The mucosal surfaces are eroded. At the
edges of the erosions, the epithelium is mauve/grey
and a pale network (Wickham’s striae) is sometimes
seen. The vaginal lesions in erosive lichen planus are
important to recognise early and start treatment as
they can lead to scarring and complete stenosis. The lesions consist of friable telangiectasia with patchy erythema, which are responsible for the common symptoms of post-coital bleeding, dyspareunia and a variable discharge which is often serosanguinous. As erosions heal, synaechiae and scarring can develop. This type is also seen in the oral mucosa although synaechia is uncommon

Question 6

Complications of lichen planus

Answer 6

. Scarring, including vaginal synaechia.

. Development of SCC. The incidence can be as high as 3%

Question 7

Diagnosis of lichen planus

Answer 7

. Characteristic clinical appearance. Involvement of the
vagina excludes LS. Skin changes elsewhere can be helpful but overlap between lichen planus and LS is
described. Immunobullous disorders such as pemphigus can look clinically similar to erosive lichen planus.
. Histopathology of vulval biopsy: irregular sawtoothed
acanthosis, increased granular layer and basal cell liquefaction. Band-like dermal infiltrate mainly lymphocytic. Features may be non-specific and can overlap with LS and Zoon’s.
- Polygonal flat topped violaceous purpuric plaques and papules with white fine reticular pattern (Wickam striae)

Question 8

Investigations in lichen planus

Answer 8

. Biopsy: is a necessity if the diagnosis is uncertain or
coexistent VIN/SCC is suspected. Direct immuno-
fluorescence should be performed if an immunobullous
disease is considered in the differential diagnosis. Only 25% are classic on biopsy and clinicopathological
discussion is important.
. Investigation for autoimmune disease especially of
the thyroid.
. Skin swab: to exclude secondary infection especially
of excoriated lesions as clinically indicated.
. Patch testing: if secondary medicament allergy or
contact dermatitis suspected.
. Whilst a link with hepatitis C and sometimes B has
been noted in some countries, there is no evidence of
increased incidence in the UK and routine screening
is not thought necessary.

Question 9

Treatment of lichen planus

Answer 9

. Ultra-potent topical steroids, e.g. Clobetasol proprionate
. Maintenance treatment may be required and can
either be with weaker steroid preparations or less
frequent use of potent steroids.
. Vaginal corticosteroids: delivery of corticosteroids
to the vagina is not easy. A proprietary preparation
containing hydrocortisone (Colifoam), introduced
with an applicator, is useful. Prednisolone suppositories may be used in more severe cases.