Seborrhoeic
Keratoses
Definition
Seborrhoeic keratoses, also known as basal cell papillomas,
are warty-like thickenings of the surface layer of the skin
(epidermis).
Incidence,
Age and Sex
These are extremely common, harmless, growths of the skin.
They occur with increasing frequency with increasing age.
Males and females are equally affected.
Causes
and Preventions
The thickened growths usually start to appear after the
age of 40. They may occur in families but are not infectious.
They are not related to sun exposure.
Signs
and Symptoms
Most of these harmless growths occur on the trunk. Occasionally
they may occur at other sites such as on the forehead, temples
and lower legs. They start with a slightly roughened area
of the skin which may be a light brown or yellowish colour.
As they become more thickened then they become more warty
in texture and blacker in colour. They may occur as a solitary
roughened patch. In practice individuals with these tend
to develop more with increasing age. Some individuals develop
many hundreds of lesions.
Some
seborrhoeic keratoses may itch from time to time. Roughened
areas of the skin may be knocked off and some bleeding may
occur if the lesions are caught.
Larger growths or growths around collars, waistbands or
under bra-straps may cause discomfort and irritation from
catching on clothing.
Complications
of Disorder
As some seborrhoeic keratoses may have deep pigmentation
they can be confused with melanoma. Melanoma being a potentially
fatal skin cancer needs to be considered in the diagnosis
of any pigmented skin lesion. In practice for the majority
of seborrhoeic keratoses it is easy to differentiate a harmless
seborrhoeic keratosis from a potentially more serious melanoma.
If there is any doubt about the diagnosis however specialist
advice may be required.
Occasionally
some individuals may develop hundreds of seborrhoeic keratoses
predominantly on their trunk over a period of a number of
weeks. This is a very rare occurrence and if this occurs
further investigation may be required as occasionally underlying
stomach problems may be found.
Tests
Reassurance is required that seborrhoeic keratoses which
are common and harmless are not mistaken for melanoma. This
may in some individuals require removal of the lesion to
make the diagnosis in doubtful cases.
Treatment
As seborrhoeic keratoses are harmless skin lesions no treatment
is therefore required. However as they can be cosmetically
unsightly and embarrassing and can cause problems with catching
and itching then many individuals will seek active treatment.
They do not respond to diet or the application of creams.
The
simplest method of treatment is freezing with liquid nitrogen
which is available from dermatologists or from some general
practitioners. If liquid nitrogen is well tolerated then
tens of lesions may be treated at one session. Repeat treatments
may be required when new lesions develop.
Larger
lesions can be effectively removed by scraping away at the
surface with an instrument known as a curette. This procedure
is performed under local anaesthetic and again several lesions
can be treated at one go. Excision of the lesions should
not be routinely undertaken unless there is diagnosis difficulty.
Excision of lesions will result in scarring which can be
avoided by using the freezing technique.
Outcome
Once lesions develop then they tend to persist. Some may
increase and become more unsightly with increasing age.
Provided skin cancer is excluded then there should be no
medical concern about these lesions.
