Transcript The itchy patient - Bath Dept of General Practice

Itchy rashes
Maggie Kirkup
SpR Dermatology
Royal United Hospital
Bath
How common is skin disease in
the population?
1. Questionnaire - 1217 unselected adults
Skin accounted for 25% of 6009 ailments
(Market Research Group 1982)
2. Examination - 55% of population had a
skin complaint, 22.5% worthy of medical
attention1.
1Rea et al Br J Prev Soc Med 1976; 30: 107-14
Describe itch
• “local discomfort or irritation of the skin,
prompting the sufferer to scratch or rub the
affected area. It is the main symptom of skin
disease”
• “a peculiar tingling or uneasy irritation of the skin
that causes a desire to scratch the affected area”
“It feels as though every nerve ending in my
body is attacking me intensely at my ankles,
feet, lower legs, neck, under the breasts
(even the nipples tingle). It's absolutely
horrendous! My hands grow red as a beet
and the itching nearly takes the skin off my
hands as I scratch.”
All Party Parliamentary Report on Impact of Skin Disease.
2003
“ It’s like someone tickling you under the
skin”
Pathophysiology
• Debate continues over whether there are
specific nerve endings for itch
• Possibly more than one mechanism
Pathophysiology of itch
• Free nerve endings
Fibres most concentrated
in wrists and ankles
Unmyelinated C fibres to
dorsal horn in spinal
cord
• Scratching is a spinal
reflex response
Ascends to cerebral cortex
via spinothalamic tract
• Skin inflammation
• Psychological concerns
• Chemical mediators
Substance P
Opioid and non-opioid
peptides
Somatostatin
Neurokinin A
Histamine
Serotonin
Prostaglandins
• External mediators
Environmental heat or
dryness
Approach to diagnosis of itching
• History
including onset, duration, pattern, effect on sleep,
previous skin disease, contacts, other medical
problems, drugs, response to treatment so far.
• Skin examination
features of rash, post-inflammatory changes, signs
of scratching
• General examination
Signs of itching
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distress
excoriation
lichenification
shiny nails
weals
nodules
Factors affecting presentation of
itchy condition
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age
self-control/ social setting/ distractions
other medical conditions/ ability to scratch
site of itch
specific skin condition
duration
Causes of itch
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skin disorders
systemic disorders
psychogenic
habit / itch-scratch cycle
physiological?
Causes of itch
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skin disorders
systemic disorders
psychogenic
habit / itch-scratch
physiological?
Common itchy skin disorders
in the young
Common itchy skin disorders
in the young
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infestations: scabies, lice, threadworms
eczemas
urticaria
psoriasis (sometimes)
insect bites – papular urticaria
pityriasis rosea
viral exanthems
Common itchy skin disorders
in the young
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infestations: scabies, lice, threadworms
eczemas
urticaria
psoriasis (sometimes)
insect bites – papular urticaria
pityriasis rosea
viral exanthems
Common itchy skin disorders
in the young
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infestations: scabies, lice, threadworms
eczemas
urticaria
psoriasis (sometimes)
insect bites – papular urticaria
pityriasis rosea
viral exanthems
Common itchy skin disorders
in the young
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infestations: scabies, lice, threadworms
eczemas
urticaria
psoriasis (sometimes)
insect bites – papular urticaria
pityriasis rosea
viral exanthems
Common itchy skin disorders
in the young
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infestations: scabies, lice, threadworms
eczemas
urticaria
psoriasis (sometimes)
insect bites – papular urticaria
pityriasis rosea
viral exanthems
Common itchy skin disorders
in the young
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infestations: scabies, lice, threadworms
eczemas
urticaria
psoriasis
insect bites – papular urticaria
pityriasis rosea
viral exanthems
Common itchy skin disorders
in the young
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infestations: scabies, lice, threadworms
eczemas
urticaria
psoriasis (sometimes)
insect bites – papular urticaria
pityriasis rosea
viral exanthems
Common itchy skin disorders in
mature adults
Common itchy skin disorders in
mature adults
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infestations: scabies
eczemas / nodular prurigo/ xerosis
urticaria
psoriasis (sometimes)
lichen planus
bullous pemphigoid
polymorphic light eruption
Common itchy skin disorders in
adults
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infestations: scabies
eczemas / nodular prurigo/ xerosis
urticaria
psoriasis (sometimes)
lichen planus
bullous pemphigoid
polymorphic light eruption
Common itchy skin disorders in
adults
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infestations: scabies
eczemas / nodular prurigo/ xerosis
urticaria
psoriasis (sometimes)
lichen planus
bullous pemphigoid
polymorphic light eruption
Common itchy skin disorders in
adults
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infestations: scabies
eczemas /nodular prurigo/ xerosis
urticaria
psoriasis (sometimes)
lichen planus
bullous pemphigoid
polymorphic light eruption
Common itchy skin disorders in
adults
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•
•
•
•
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•
infestations: scabies
eczemas/ nodular prurigo/ xerosis
urticaria
psoriasis (sometimes)
lichen planus
bullous pemphigoid
polymorphic light eruption
Common itchy skin disorders in
adults
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eczemas / nodular prurigo/ xerosis
urticaria
psoriasis (sometimes)
infestations: scabies
lichen planus
bullous pemphigoid
polymorphic light eruption
Less common skin complaints
which itch
• dermatitis herpetiformis
• aquagenic pruritus
• T cell lymphomas
• pityriasis rubra pilaris
• onchocerciasis etc etc
Localised itch
• Anogenital/ pruritus ani:
think of threadworms, lichen sclerosis, lice,
scabies, contact dermatitis
• Hands:
eczemas, scabies, contact dermatitis
Localised itch
• Anogenital/ pruritus ani:
think of threadworms, lichen sclerosis, lice,
contact dermatitis
• Hands:
eczemas, scabies, contact dermatitis
Localised itch
• Flexures:
atopic/ seborrhoeic eczema, scabies
• Scalp:
lice, seborrhoeic dermatitis, psoriasis
• Any area:
discoid eczema, lichen simplex chronicus, contact
dermatitis
Less common causes of localised
itch
• brachioradial pruritus
• notalgia paraesthetica
Skin disorders which don’t
(usually) itch
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psoriasis ?
acne/ folliculitis
vasculitis/purpura
erythema multiforme
secondary syphilis
Causes of itch
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skin disorders
systemic disorders
psychogenic
habit
physiological?
Systemic causes of itch
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liver disease
renal failure
iron deficiency
metabolic:
protein, zinc, calcium, vitamin deficiencies
• thyroid disease
Systemic causes of itch (part 2)
• diabetes
• malignancies: lymphoma, PRV,
leukaemias, myeloma
• pregnancy
• neurological
• drugs
Screening investigations in itchy
patients with no rash
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Full blood count
Ferritin
Renal function
Liver function
Thyroid function
? Chest X ray
Psychogenic itch
• epidemic forms - hysteria
• delusional parasitosis
• habit - itch/scratch cycle
Management of itching
• Treat the cause
• Treat the itch
Management of itching
• There is no specific drug for itch
Management of itching
• keep looking for a cause
• avoid aggravating factors
temperature, humidity, bedding, clothing
• reduce damage from scratching
clothing, bandaging, cut nails
Management of itching
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topical agents
gadgets
systemic agents
psychological interventions
Topical agents
• emollients
• antihistamines* - doxepin (Xepin)
• unknown mechanism crotamiton (Eurax)
calamine
• counter-irritant - capsaicin, menthol
• local anaesthetics *
*Risk sensitization
• paste bandages
Management of itching
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topical agents
gadgets
systemic agents
psychological interventions
Management of itching
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topical agents
gadgets
systemic agents
psychological interventions
Systemic agents
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Antihistamines ?
Opiod antagonists
Ondansetron
Rifampicin
Cholestyramine
Tricyclic antidepressants
Thalidomide
Phototherapy
Management of itching
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topical agents
gadgets
systemic agents
psychological interventions
Psychological and alternative
interventions
• Biofeedback
• Behaviour therapy*
• Relaxation techniques
• Acupuncture
• Hypnotherapy
• Homeopathy
• Self-help groups
*Melin I et al Behavioural treatment of scratching in patients with atopic dermatitis.
Brit J Dermatol 1986; 115: 467-74
Summary
• Itching can be caused by skin disease,
systemic disease, psychogenic factors or
idiopathic
• Management and investigation need to be
tailored to the patient’s condition and
circumstances