Dermatology clinic
Sunshine makes us feel better but it can also cause us a lot of damage. This month Susannah Baron discusses how to manage malignant melanoma
The storm clouds have lifted and summer
has finally arrived. So begins the British
seasonal madness of throwing off clothing,
exposing as much sun starved flesh as
possible to any available rays, and joining the
huge traffic queues heading to the coast.
The summer brings a variety of problems
for the dermatologist. Many skin conditions
such as psoriasis, eczema, and acne improve
with ultraviolet exposure, although
everyone is different and some people find
that their skin rashes flare in the sun. The
summer can also be a particularly difficult
time for some people who often find it
embarrassing to remove clothing, thus
making their rashes visible to the not always
sympathetic public. People with psoriasis
have been asked to get out of public
swimming baths and children are
sometimes pulled away from people with
skin conditions as parents wrongly assume
that the rash is catching.
This man developed acute, streaky, linear erythema and bullae 24 hours after chopping
rue in his garden. This is typical of phytophotodermatitis, as the rash has developed
where the plant was in contact with the skin, and these areas exposed to sunlight.
The active ingredient in the plant is furocoumarins which are psoralens, and the
phototoxic reaction develops with their simultaneous exposure to light in the 320-
380 nm waveband.
The sun can bring out a variety of
other problems, from sunburn to
phytophotodermatitis (don't panic:
phyto=plant, photo=light, and
dermatitis=skin rash). This often acute and
vesicular rash develops in sun exposed
areas after someone has had contact with a
particular phototoxic provoking plant-for
example, giant hogweed or rue.
Polymorphic light eruption is a common
sensitivity to ultraviolet light, which results in
a pruritic eruption on exposed areas,
classically 24 to 48 hours after sun exposure.
This can be prevented in subsequent years
by having a course of ultraviolet light before
the summer.
Many skin diseases are worsened by
Sunshine - for example, lupus erythematosis
and porphyria, and many drugs are
photosensitising - for example, phenothiazines,
tetracyclines, sulphonamides, and
amiodarone.
Dermatologists are always advising sun
protection as ultraviolet exposure stimulates
moles and is implicated in all forms of skin
cancer: basal cell carcinomas, squamous cell
carcinomas, and malignant melanomas.
Sadly, although the risks of cancer are well
known people still sunbathe. It is often the
mention of the photo ageing effects of
ultraviolet light that encourages people
(especially women) to change behaviour.
Case history
A 32 year old man comes to see you in clinic
concerned about a mole on his thigh. He
tells you that the lesion was not present until
two to three months ago and it has increased
rapidly in size in the past three weeks and
has become darker in colour.
Questions
- What other points would you like to cover in the history?
- What examination would you like to do?
- What is the diagnosis and differential diagnosis?
- What is your management plan?
Answers
It is important to ask about sun exposure.
This man had lived in Australia, had
excessive sun exposure, and remembered
being sunburnt on numerous occasions. It is
also important to ask about family history of
melanoma as familial cases can occur.
The four important points in the history of the lesion are:
- Change in size
- Change in colour
- Change in shape
- Symptoms (itching, bleeding, etc)
The lesion should be measured and a
description recorded - for example, irregular
margins, irregular pigmentation, and
nodular areas. You should note and examine
all other pigmented naevi, feel for any
regional lymphadenopathy, and examine for
hepatomegaly.
Seven point checklist for moles2
Three major signs:
- Change in shape
- Change in size
- Change in colour
Four minor signs:
- l Over 5 mm in diameter
- Inflammation
- Crusting or bleeding
- Symptoms of minor irritation or itch
Any pigmented lesion with one major
and one minor sign should be considered
for an excision diagnostic biopsy. This
checklist is sensitive but not specific.
This lesion is a malignant melanoma. It
measure 7.5 mm by 8.6 mm. The differential
diagnosis is a dysplastic naevus.
The malignant melanoma should be
excised urgently and then examined
histologically. The depth to which the
malignant melanocytes have invaded is the
most important prognostic factor for the
patient. This measurement, which is made
in millimetres, is called the Breslow
thickness. This melanoma had a Breslow
thickness of 0.7 mm. Current
recommendations for surgical excision
margins are set out in the table.1
Myotome raps
Last suggested that linking movement
and voice facilitates learning myotome
innervations. (1) Stylised movements to
recited doggerel have proved successful
and entertaining; these, for both limbs,
are given below. The raps should be
done to rhythmic music, or to rhythmic
noises made by others. Repetition, of
each line and of the whole rap later,
helps reinforce memory.
Upper limb
"Snakes alive! Its C five!" (Extension and
lateral rotation of shoulder, flinging
arms out and back.)
"Down from heaven, six, seven."
(Flexion and medial rotation, bringing
arms across chest.)
"Grab some sticks, five, six." (Elbow flexion,
gathering "sticks" into bent arms.)
"Put 'em in the grate, seven, eight."
(Elbow extension, putting sticks down
and forwards.)
"Supine flicks, that's six." (Close fist,
extend thumb, flick outwards.)
"Pronate, seven, eight." (Same, but flick
thumb inwards.)
"Royal wavin', six and seven." (Flex and
extend hand from wrist.)
"Grab it tight, seven and 'ight." (Make
and extend fist.)
"Last have fun with T one!"
(Adduct/abduct fingers, thumb opposition.)
Lower limb
"Flex hip, across with knee, that's done
by L two, three." (Flex hip and knee,
bring knee across body.)
"Thigh back, knee out to forty five,
remember that's L four and five."
(Extend and laterally rotate hip.)
"Now kick to score, L three and four."
(Extend flexed knee.)
"Heel to bum, L five, S one." (Flex knee,
heel to buttock.)
"Toes up to jive, L four and five." (Lift
foot, dorsiflex (extend) ankle.)
"Stick 'em in your shoe, S one and two."
(Flex ankle and point toes.)
"Invert your claw, just L four." (Invert
foot.)
"Charleston, L five, S one." (Lift foot,
evert.)
I thank the late Professor R J Last, whose
idea I merely developed, and my students
for their encouragement.
N A Locket visiting research fellow, University of Adelaide, South Australia
alocket@medicine.adelaide.edu.au
- Last RJ. Anatomy, regional and applied. 7th ed. Edinburgh: Churchill Livingstone, 1984:29.
There are approximately 10 new cases of
melanoma per 100 000 of the population a
year in Europe and the United States, with a
greater incidence in Australia and New
Zealand. It is important to follow up patients
whose melanomas have been excised. The
main objectives are to detect early
recurrence, to detect any new primary
lesions, and to reinforce educational advice
regarding sun exposure. At each follow up
visit patients should have a full skin
examination and an examination of regional
lymph nodes. Follow up with clinical
photographs may be helpful if patients have
multiple or atypical naevi. There are no firm
recommendations regarding frequency of
follow up, but it is suggested that patients
with melanomas greater than 1 mm in
Breslow thickness should be followed up for
five years and those with thinner lesions can
be discharged after three years.
Susannah Baron, specialist registrar in dermatology, Leeds
Email: zannerzu@aol.com
studentBMJ 2001;09:217-260 July ISSN 0966-6494
- British Association for Dermatology. Guidelines for the management of primary malignant melanoma of the skin. London: British Association of Dermatology, 2000.
- MacKie RM. Clinical dermatology textbook. Oxford: Oxford University Press, 1997.
