What are the rashes on my limbs ? ( 21/6/2015 HKDU PMH ) Dr. Lee Tze Yuen M.D.(H.K.) F.R.C.P.(Edin.) F.H.K.A.M.(Med.) Hon. Clinical Associate Professor Faculty of Medicine H.K.U.
What are the rashes on my
limbs ?( 21/6/2015 HKDU PMH )
Dr. Lee Tze Yuen
M.D.(H.K.) F.R.C.P.(Edin.) F.H.K.A.M.(Med.)
Hon. Clinical Associate Professor
Faculty of Medicine H.K.U.
Pigmented band of finger nail
History:
A teenage boy had a brownish band
running from the cuticle to the distal
edge of his finger nail.
Question:
Should a biopsy be taken from his nail?
Longitudinal melanonychia (甲黑)
Causes: normal variation --Asians 11%
1. increased melanin synthesis
2. tumors of melanocytes
beneign – naevus
malignant – malignant melanoma
C/F: Tan, brown or black longitudinal streak
within nail plate.
Longitudinal melanonychia
Signs suggestive of possible malignancy:
1. widening or darkening of the pigmented band
2. peri-ungal spread of pigmentation to proximal
or lateral nail fold (Hutchinson’s sign)
3. ill-defined, irregular lateral border
4. band is black or variegated
5. lesion begins after 50
Rashes at flexures
History:
A 13 years old boy has long history of dermatitis
requiring frequent use of topical steroids. His
mother was very worried that the steroid may affect
his normal growth.
Questions:
“ Dr., can you do something about it? “
Non-steroidal immunomodulators
( e.g. tacrolimus / pimecrolimus )
Mechanism: inhibits T cell proliferation
Adantage: do not have side effects of steroids
useful in dermatitis :
- intermittent use to prevent flares
- at eye-lids, face and neck
-Rx of early lesions
- should not be used for children <2
Non-steroidal immunomodulators
( e.g. tacrolimus /pimecrolimus )
Side effects:
- burning sensation --very common
- increased sensitivity to heat and cold
- flu-like symptoms
- infections like herpes simplex, herpes
zoster, impetigo
- folliculitis
Linear itchy rashes at
thigh
History:
A 45 years old man complained of a linear pigmented
lesion at his thigh.
It appeared to diminish a bit after treatment with
steroid cream but reappeared soon after it was
discontinued.
Question:
“Dr., what is the linear rash at my thigh?”
Lichen striatus
A form of eczema arranged in a linear
form
- Responds well to topical steroids
- Easily confused with linear epidermal
naevus (a beneign tumour arising from
epidermal cells)
Red weepy rashes at groin
History:
A 62 years old man complained of itchy, red,
weep rashes at his left groin.
Questions:
1. What physical signs were shown in his
lesion?
2. What is your diagnosis?
Radiodermatitis
Physical signs:
Erythema, telangiectasia, fibrosis, ulceration,
pigmentary changes, well-demarcated or
angulated borders
Rx:
1. symptonatic Rx with topical steroids
2. watch out for malignant and prenalignant
conditions
Wide spread erosions
History:
A teenage school boy has long history of itchy
rashes at his trunk and limbs.
He had sudden onset of low grade fever,
malaise and wide spread bubbles and
erosions at his upper limbs and trunk
Question:
What do you think is the most likely causative
agent ?
Eczema herpeticum
Herpes simplex complicating dermatitis.
C/F: similar to herpes simples but much
more severe and extensive.
Rx: requires prompt and energetic
treatment
Intensely itchy nodules
History:
A desparate 67 years old retired merchant
complained of intensely itchy lumps on his
limbs and trunk.
They responded poorly to all the medications
given so far.
Questions:
1. What is your diagnosis?
2. What is your Rx of choice ?
Nodular prurigo (結節性癢疹)
Definition: A chronic inflammatory
disease of the skin characterized by
widespread itchy nodular lesions.
Lesions: multiple, discrete, grossly
lichenified papules and nodules with ill-
defined borders and marked excoriation
Mx of nodular prurigo
(結節性癢疹)
1. Steroids:
a) topical use of very potent steroids
b) intra-lesional steroids
2. Supportive measures
e.g. antihistamines, cutting of nails,
antibiotics…
Sharp pain and linear red
rashes
History:
A young diver was seen at the AED.
He complained of itchy and painful rashes at
his wrist since this morning.
Questions:
1. What are the common causes of linear
lesions at the wrist?
2. How should this patient be treated?
Jelly fish dermatitis
Mechanism: toxins from nematocytes
C/F:
- sudden sharp pain followed by appearance
of characteristic rashes
P/E:
- linear, erythematous lesions with papules
or blisters on top
Jelly fish dermatitis
Treatment:
1. Soak in hot (not scalding ) water to
denature proteins from nematocytes
2. Use of potent topical steroids,
analgesics and antihistamines
Scaly feet for years
History:
This middle age man had dry scaly rashes of his feet for many years. The rashes were neither itchy nor painful.
He had tried various moisturizers and topical steroids which gave unsatisfactory response.
Question:
Suggest one important diagnostic test for this
patient.
Hyperkeratotic type of tinea pedis
Often not itchy—patient may not know that
they had the infection for years!
C/F:
- affecting the soles, heels and sides of feet
- more pronounced at lines and creases
Common organism: trichophyton rubrum
Itchy painful rashes of fingers
History:
A 57 years old H.W. complained of itchy and
painful rashes her fingers.
Questions:
1. What abnormal signs do you notice in this
patient’s hands?
2. How would you manage this patient?
Chronic paronychia
(慢性甲溝炎)
Signs of chronic paronychia:
- loss of cuticle
- periungal erythema
- periungal swelling
- gap between nail plate and nail fold
- others: nail deformities
pus on compression
- often associated with changes of chronic
dermatitis
Chronic paronychia
(慢性甲溝炎)
Management of chronic paronchia:
1. Keep hands dry—most important
2. Topical anti-fungal + mild steroid
e.g. 1 % hydrocortisone and clotrimazole
3. Rx of chronic dermatitis
Dr., Is this “食肉菌 “ ?
History:
A young athlete was very worried because
the superficial parts of his toes and soles
were gradually “ being eaten by some
unknown organism”.
Questions:
1. Is this “食肉菌” ?
2. What is your treatment of choice?
Pitted keratolysis
(凹陷性角質層分離)
A superficial bacterial infection of the toes and soles by corynebacteria.
They produce proteolytic enzymes which digest keratin, giving rise to superficial, circular, punch-out erosions.
Rx:
A) topical: fusidic acid, clotrimazole,
Whitfield’s ointment
B) oral antibiotics e.g. erythromycin
Painful papule at sole
History:
This 18 years old university student
complained of a painful lump at his heel.
“ Can you remove the wart for me, Dr.?”
Question:
What would you do?
Corn of sole (雞眼)
Corn is a localised hyperkeratosis of the skin due to repeated pressure or trauma.
Corn Vs Wart:
1. Corn always appears at pressure points
2. Paring - corn becomes more and more
normal looking after being pared.
- warts showed dark spots or bleeding
points
Asymptomatic scaly palms
History:
A 20 years old clerk felt socially embarrassed because of recurrent episodes of scaly rashes on his hands. The lesions were neither itchy nor painful.
Repeated scrappings for fungus were negative.
Question:
“ What is the cause of the scaling? ”
Keratolysis exfoliativa
C/F:
- superficial exfoliation of palms and soles
- usually asymptomatic
- no inflammation
- culture for fungus negative
Path: a mild form of dermatitis
Rx: - reassurance
- emollients or mild steroids
- Whitfield’s ointment
Lumps at dorsum of hand
History:
The owner of a shop selling tropical fishes noticed a red, slightly tender lump on his hand for 9 months.
Rx with ampiclox and topical anti-fungal cream showed no response.
Questions:
1. What investigation would you perform for this
patient?
2. What is the treatment of choice for him?
Lumps at dorsum of hand
DDx: fish tank granulosum, sporotrichosis,
tuberculosis verrucosa cutis,
skin tumors
Ix: a) punch biopsy for histopathological
examination and
b) culture for AFB
Fish tank granuloma
(魚池肉芽腫)
- also known as swimming pool granuloma
- an infection caused by atypical
mycobacterium, M. marinum
- mode of transmission:
a) fish tank b) swimming pool
- sites : hands, elbows, knees
- Rx: a) septrin or doxycycline
b) rifampicin and ethambutol
Itchy rashes on feet
History:
A 45 years old executive complained of itchy red rashes at the dorsa of her feet every time she had trips abroad.
Examination showed erythematous rashes at the dorsa of her feet.
Questions:
1. What do you notice about the distribution
of the rashes?
2. What is your diagnosis?
Shoe contact dermatitis
(鞋之接觸性皮炎)
C/F:
a) changes of dermatitis
b) convex surfaces affected
infolded area (e.g. flexural creases of toes,
insteps ) spared
Common allergens: rubber accelerators,
chromium in leathers,
adhesives…
Itchy painful rashes of hands
History:
A young boy complained of itchy, dry and painful rashes at the dorsa of his hands.
He was noticed to have cystic acne and his lips were dry and scaly.
Questions:
1. What leading questions would you ask the
patient so as to find out the cause of the
rashes?
2. What is the treatment of choice for his rashes?
Asteatotic dermatitis
(乾燥性皮炎)
1. Cystic acne together with dry and scaly
lips suggested that he was having treatment
with isotretinoin ( Roaccutane, Oratane ).
Asteatotic dermatitis of hands is a very
common side effect of isotretinoin.
2. Rx of choice : 1 % hydrocortisone or
mometasone ointment
Doxycycline and isotretinoin
History:
This patient was taking oral doxycycline
from the dispenser at the same time.
Question:
What is your comment?
Cystic acne and isotretinoin
Tetracyclines must not be prescribed together
with isotretinoin !
Both can cause raised intracranial pressure!
Erythromycin can be taken with isotretinoin.
Generalised skin rashes
History:
A 23 years young man noticed malaise, headache, and low grade fever for a few days followed by the appearance of non-itchy, erythematous rashes at his palms, soles, limbs and trunk.
Question:
What is the most important investigation one
should perform for the patient?
Secondary syphilis
(二期梅毒)
Investigation: V.D.R.L. always positive
at this stage
Important to consider secondary syphilis as a possibility in all patients with generalised, symetrical lesions.
This stage is highly contagious--- do not touch the lesions with your hands!
Secondary syphilis
(二期梅毒)May mimic a large no. of skin diseases
Morphology :
- pinkish exanthema at early stage
- skin lesions: macular, papular,
papulosquamous , pustular, acneform
- mucous membranes: mucous patches,
papular lesions
- scalp: diffuse hair loss,“moth-eaten”alopecia
Thank you very much
for your attention !