Transcript Vitiligo

ULTRAVIOLET RADIATION
(UVR)
Radiation between the visible
light & X-ray sections of the
electromagnetic spectrum. (J.
Ritter)
RADIO f
IRR
VISIBLE LIGHT
UVR
NATURE OF UVR
1. Strongly absorbed in air (*shortwavelength UVR)
2. Behave like visible radiation in
terms of properties (reflection,
refraction, transmission and
absorption)
3. Transmit more energy, thus,
producing more chemical
changes not just simply heat
CATEGORIES OF UVR
UVA
Wavelength
(nm)
Other
Names
UVB
UVC
320-400
290-320
200-290
315-400
280-315
100-280
Long
Medium
Short
Blacklight
Erythemal
Germicidal
Near
Near
Far
CATEGORIES OF UVR
Near UVR- nearer the visible
light spectrum but are longer
in wavelength
*Longer wavelength are more
beneficial (BIOTIC)
Shorter wavelength are
ABIOTIC
PRODUCTIONS OF UVR
I. NATURAL WAY: SUN
II. ARTIFICIAL WAY
I. NATURAL WAY: SUN
5-10% of the sun’s energy is in
the UVR range (180-400 nm)
UVA 6.3% of sunlight during
summer; UVB 0.5%
Both UVA & UVB can be involved
in sunburn and skin diseases
II. ARTIFICIAL WAY
Passage of electric current thru gas (vaporized
mercury)
Collision with the electrons flowing between the
lamp’s electrodes
Mercury atoms become excited
Excited electrons return to particular electronic
states in the mercury atom
Release some of the energy they have absorbed
RADIATION
II. ARTIFICIAL WAY
UVR can be produced if the
temperature is high enough
and pressure is low
UVR=
T° +
P°
ARTIFICIAL UVR APPARATUS
John Low
Wadsworth
1. Kromayer lamp
2. Fluorescent lamp
3. Medium pressure
mercury arc lamp (Alpine
Sunlamp)
4. Low pressure mercury
vapor discharge tubes
1. Water-cooled lamp
(Kromayer lamp)
2. Fluorescent lamp
3. Air-cooled lamp (Alpine
Sunlamp)
A. KROMAYER LAMP
a.k.a. water-cooled lamps
requires pre-heating of 5
minutes
a medium pressure mercury
vapor designed to be used in
contact with the tissue (i.e.
treatment of localized pressure
areas and ulcers).
A. KROMAYER LAMP
wavelengths of the rays produced
are concentrated at 366 nm but a
wide range of both UVA & UVB
are produced.
B. FLUORESCENT LAMPS
low-pressure mercury discharge
tubes with a phosphor coating on
the inside
absorbs short UVR which causes
excitation of the phosphor atoms
and remission at a longer
wavelength
B. FLUORESCENT LAMPS
gives considerable UVA & UVB
output; NO UVC
more commonly used for
Psoriasis affecting large body
areas
C. ALPINE SUN LAMP
a.k.a air-cooled lamps
generally used for treatment of
generalized skin conditions like
Acne and Psoriasis
Usually applied at a distance of
45-50 cm
D. LOW PRESSURE MERCURY
VAPOR DISCHARGE TUBES
Components:
a. Tube or envelope made of quartz
or special glass to allow UVR to pass
through
b. Metal electrodes sealed in the
ends of the tube
c. Electric circuit to regulate electric
current
PHYSIOLOGIC EFFECTS
1. Erythema or redding & tanning
- only encountered when UVB (at
250-297 nm) treatment is used.
Minimal Erythemal Dose = smallest
UVR dose to result in erythema
that is just detectable by eye
between 8-24 hrs after exposure
PHYSIOLOGIC EFFECTS
2. Pigmentation
- results from formation of melanin
in deep regions of the skin &
migration of melanin noticeable
about 2 days after exposure
- UVB at 300 nm
PHYSIOLOGIC EFFECTS
3. Hyperplasia
- occurs at 72 hrs using UVB
4. Increase skin growth
- increase keratinocyte cell
turnover so that skin grows more
rapidly for a time leading to
shedding of most superficial cells
at an earlier stage
PHYSIOLOGIC EFFECTS
5. Vitamin D production
- UVB convert sterols in the skin (7dehydrocholesterol) to vitamin D
at 280-300 nm
6. Destruction of bacteria
-occurs by suppressing DNA and
RNA synthesis at UVB at 250270 nm
PHYSIOLOGIC EFFECTS
7. Wound healing
- using UVB at 260-280 nm
8. Increase production of RBC
9. Stimulation of steroid metabolism
- UVR promotes vasomotor responses
causing antirachitic effect
PHYSIOLOGIC EFFECTS
10. Immunosuppressive effects
- UVB destroys Langerhans cells &
stimulate proliferation of
suppressor T cells
PHYSIOLOGIC EFFECTS
11. Conjunctivitis / photokeratitis /
cataract
- conjunctivitis occur at UVB with
270 nm
- cataracts at UVA since it can
pass thru the eye’s lens
PHYSIOLOGIC EFFECTS
12. Premature aging of the skin
(dry, wrinkled, decreased function
of sebaceous and sweat glands)
13. Skin cancers
14. Psychological effects
INDICATIONS OF UVR
1. Skin diseases
a.) Psoriasis treatment
b.) Acne vulgaris treatment
 To
accelerate skin growth, help
control infection, sterilize skin
surface temporarily
INDICATIONS OF UVR
2. Healing of wounds (venus
ulcers & pressure sores)
 To
increase rate of skin growth and
to provide antibiotic effect
INDICATIONS OF UVR
3. Vitiligo
 Tanning
and thickening of the
skin
4. Protection of hypersensitive skin
INDICATIONS OF UVR
5. Alopecia
6. Treatment of vitamin D
deficiency
INDICATIONS OF UVR
7. Pruritus due to biliary cirrhosis
or uremia
8. Jaundice for newborn babies
CONTRAINDICATIONS
1. Acute skin conditions (acute
eczema, dermatitis)
2. Skin damage due to ionizing
radiations like deep X-ray therapy
CONTRAINDICATIONS
3. Systemic lupus erythematosus
can be triggered or exacerbated
4. Photoallergy / photosensitivity
(albinism will not tolerate UVR)
CONTRAINDICATIONS
5. Porphyrias (rare metabolic
disorder)
6. Pellagra (dermititis due to
severe niacin deficiency)
CONTRAINDICATIONS
7. Acute febrile illness (pulmonary
tuberculosis, severe cardiac
involvement, acute diabetes
mellitus)
8. Recent skin graft
PRECAUTIONS
Patients with:
a.) little pigmentation, often seen in
blondes and redheads.
b.) conditions like syphilis, alcoholism,
cardiac or renal disease, acute psoriasis,
acute eczema, elderly and infants.
PRECAUTIONS
c.) Ingested certain food like
strawberries, eggs or shellfish before
treatment.
d.) Taking any of the ff: birth control,
pills, tetracycline, diuretics and
insulin.
e.) Recent superficial heat treatment
before UVR radiation.
DANGERS OF USING UVR
1. Eyes (conjunctivitis)
2. Overdose (too long exposure; too close
to the lamp)
3. Previously protected skin
4. Electric shock
5. Burns
6. Chill
7. Sensitizers
8. Change of lamp
LEVELS OF UVR ERYTHEMA
E1
6-12 hrs
E2
6 hrs
E3
3 hrs
Mildly
pink
Definite
pink-red;
blanches
on
pressure
Approx.
duration
of
erythema
Less
than 24
hrs
2 days
Very
red;does
not
blanches
on
pressure
3-5 days
Skin edema
None
None
Some
Latent
period
Appearan
ce
E4
Less than
24 hrs
Angry red
A week
Blisters
LEVELS OF UVR ERYTHEMA
E1
E2
E3
E4
Skin
discomfort
None
Slight
soreness;
irritation
Hot&
painful
Very
painfu
l
Desquamatio
n
None
Powder
y
In thin
sheets
Relation to
dose causing
E1
1
2.5
5
In
thick
sheets
10
SELECTION OF DOSAGE LEVEL
DOSAGE
FREQUENCY
1. E1 or Minimal Erythemal
Dose may be given to total body
area
2. E2  up to 20% of total body
area
Given daily
3. E3  up to 250 square cm of
normal skin
Every third or fourth
day
4. E4  up to 25 square cm of
normal skin
Once a week or every
forth night
Every second day
CALCULATION OF UVR DOSAGE
Basis: determined by performing
skin test to get MED or E1
Two units of measurements to
consider:
a.) length of time (seconds)
b.) distance from the lamp (mm)
CALCULATION OF UVR DOSAGE
Levels of dosage intensity
a.) E1= determined by the skin
test
b.) E2= 2.5 x E1
c.) E3= 5 x E1
d.) E4= 10 x E1
If the E1 of the patient is 50 s at a
distance of 200 mm, find E3 at
200 mm.
CALCULATION OF UVR DOSAGE
Progression of dosage:
a.) E1 is progressed by 25% of the
preceding dose
b.) E2 is progressed by 50% of the
preceding dose
c.) E3 is progressed by 75% of the
preceding dose
If E1 is 30 s at 200 mm, find the
second progression (P2E1).
CALCULATION OF UVR DOSAGE
Alteration of intensity with distance
-guided by Law of Inverse Square
which states that as the distance
between the source and the patient
increases, the intensity decreases in
proportion to the square of the
distance.
Formula: I = 1/ d2
nt= ot x nd2
od2
CALCULATION OF UVR DOSAGE
Using Kromayer lamp:
-use the levels of dosage for intensity
since the distance is always at 25
mm.
Using air-cooled lamps:
-distance is from the burner of the
lamp to the patient and follow the
Inverse square law formula.
Using the kromayer, if the E1 of the
patient is 2 s I/C, find the E1 at
100 mm.
Using the air cooled lamp, if the E1
at 400 mm is 30 s, find the E1 at
200 mm.
CALCULATION OF UVR DOSAGE
Using an applicator:
1.) Compute for coefficient of the
applicator:
*Length of applicator in mm divided
by 25
2.) Compute for applicator dose:
*in-contact dose (secs at mm) x
coefficient of applicator (in mm)