Transcript photosensitive

Photosensitive disorders
and Urticaria
Sunlight and Skin

Major source of UV and visible radiation
interacting with human skin.

UV radiation : UVC: 200-290 nm
UVB: 290-320 nm
UVA: 320-400 nm

Visible radiation: 400-760 nm
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Infrared radiation:760 -100,000 nm

Normal effects of sun exposure on skin:
Sunburn, Tanning, Photoaging, Vitamin D
synthesis.
Skin Phototypes(Fitz Patrick Classification)
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I - always burns, never tans
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II - always burns, minimally tans
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III - burns moderately, gradually tans
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IV - burns minimal, always tans
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V - burns rarely , severely tans
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VI - deeply pigmented.
Indian skin phototypes: Type IV-VI
Classification of Photosensitive disorders
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Genodermatoses
◦ Xeroderma pigmentosum, Bloom’s syndrome,
Cockayne syndrome
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Idiopathic
◦ Polymorphic light eruptions, Actinic prurigo,
solar urticaria
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Phototoxic and photoallergic reactions
◦ Reactions induced by topical/systemic drugs,
chemicals or contactants
Contd…
Classification of Photosensitive disorders

Metabolic
◦ Porphyria, Pellagra
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Tumours
◦ Basal cell ca, Squamous cell ca, Melanoma,
Actinic keratoses.
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Diseases aggravated by sun exposure
◦ Lupus Erythematosus, Rosacea,
Dermatomyositis, Acne, Psoriasis, Pemphigus,
Atopic dermatitis, Airborne Contact dermatitis
Polymorphous light eruption (PMLE)

Most common photodermatoses
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Idiopathic, probably immunological
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Younger age, Females
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Recurrent pruritic lesions on photo exposed
areas within minutes to hours after sun
exposure.
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Clinical patterns:
◦ Macular, papular,papulovesicles,
plaque,lichen-nitidus like lesions.
Polymorphous light eruption (PMLE)
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Differential Diagnosis:
◦ Prurigo
◦ Erythema multiforme
◦ Lichen Simplex chronicus
◦ Atopic dermatitis
Photocontact dermatitis
PHOTOTOXIC
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Common
Non immunological
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Sunburn
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Clinically diagnosed
PHOTOALLERGIC
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Less Common
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TYPE IV
Hypersensitivity
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Eczematous
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Photo patch test
Systemic/ topical drugs, chemicals contactants in
combination with UVA spectrum induces
phototoxic and photoallergic reactions.
Phototoxic reactions
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Topical:
◦ Perfumes, Dyes, psoralens, tars, plants (lime,
celery)
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Systemic:
◦ Psoralen, Tetracycline, Phenothiazine
Photoallergic reactions
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Topical:
◦ Perfumes (soaps, aftershave) sunscreens
(PABA)neomycin, halogenated compounds
parthenium (congress grass)
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Systemic:
◦ NSAIDS, phenothiazine, thiazides.
Approach to photosensitive disorder
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Detailed history :
◦ Age/ Sex
◦ Occupation, Hobbies
◦ Family h/o similar disease
◦ Time interval between exposure & symptoms
◦ Contactant, drug history
◦ Cosmetics, sunscreen usage.
Approach to photosensitive disorder
Clinical diagnosis :
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Photoexposed areas:
◦ Face, ‘V’ area& nape of neck, dorsae of hands
& feet, extensors of arms & legs (check
clothing used)
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Spared areas:
◦ Under hair fringe, chin, nose, upper eyelids,
behind ears.

Morphological pattern depends on etiology
Investigations
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Depending on etiology :
◦ Connective Tissue diseases, Metabolic,
Genetic AnA, dsDNA, porphyrin levels
(blood, urine,stool), Chromosomal
analysis, cell mutation studies, DNA
repair assesment
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Biopsy
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Photo testing
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Photopatch testing
Treatment: Photoprotection
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Natural: Ozone, Melanin, Keratin.
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Physical: Clothing, broad rimmed hats,
umbrellas.
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Topical: Sunscreens, UVA, UVB therapy.
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Systemic: Beta carotene, Chloroquin,
Hydroxychloroquin, PUVA
Treatment of causative factor
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Removal of offending drug/chemical/contactant
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Steroids (topical/systemic)
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Immunosuppressives (Azathioprine,
cyclosporin, Thalidomide)
Sunscreens - Topical
Physical
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Reflect, scatter light
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Zinc oxide
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Titanium dioxide
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Ferrous oxide
Chemical
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Absorbs light &
prevents penetration
through skin
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Anthranilates,
benzophenones,
cinnamates, salicylates
Sunscreens - Topical
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Broad spectrum - UVA & UVB protective
SPF 15 or higher in Indian skin
Proper application & use in all seasons needed.
Liberal and uniform application to photo exposed
areas, half an hour prior to sun exposure.
1ml – Face
–
Female
1.5ml – Face – Male
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Frequent reapplication if involved in vigorous
exercise, swimming.
Sunscreens - Topical

Broad spectrum - UVA & UVB protective
SPF 15 or higher in Indian skin
Proper application & use in all seasons needed.
Liberal and uniform application to photo exposed
areas, half an hour prior to sun exposure.
1ml – Face
–
Female
1.5ml – Face – Male

Frequent reapplication if involved in vigorous
exercise, swimming.
Urticaria
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It is a reaction pattern consisting of
erythematous, transient, itchy swellings
(wheals) on the skin
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Urticaria is derived from the word “Urtica” (in
Latin = Stinging Nettle)
Pathogenesis
Enhanced vasodilatation + Vaso permeability
Plasma leakage
Wheals
Histamine stimulates nerve endings
Pruritus
Neuro-peptide release
Skin response (flare)
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
Response to histamine release from cutaneous mast
cells
Often seen with Angioedema
Causes
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Exogenous
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Endogenous
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Physical
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Emotional stress
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Idiopathic
Contd…
Causes
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EXOGENOUS
◦ Inhalants: pollens, house dust, fungi, dander.
◦ Ingestants: Foods: fish, egg, brinjal, food
additives, dyes, preservatives.
◦ Drugs: penicillin, NSAIDs, sulfonamides.
◦ Contactants: beestings, insect bites, plants.
Causes
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ENDOGENOUS
◦ Infections:
Gastrointestinal, respiratory, urinary tract
infections
Bacterial, protozoal, helminthic, viral (CMV,
EBV, HSV)
◦ Systemic diseases:
Hashimoto's Thyroiditis
Systemic Lupus Erythematosus
Chronic active hepatitis
Malignancies
Causes
PHYSICAL URTICARIA
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Cold Urticaria
◦ Affects hands, ear, nose and lateral thighs
Cholinergic Urticaria
◦ Fever
◦ Hot baths
◦ Exercise-Induced Urticaria
Solar Urticaria (Sun induced)
Pressure
◦ Tight clothing
◦ Soles of foot and other weight bearing points
◦ Dermographism
Types of urticaria by duration:
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Acute Urticaria (present hours to weeks)
◦ Idiopathic in 75% of cases
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Chronic Urticaria (persistent beyond 6 weeks)
◦ Idiopathic in 95% of cases
◦ May be related to autoantibody to IgE
Clinical features:
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Symptoms
◦ Pruritus
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Signs
◦ Characteristics
 Hives or wheals
 Spreads with scratching and coalesce to form
large patch
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Course of Lesions
◦ Lesions last 90 minutes to 24 hours
Dermographism
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Dermographism is a condition where linear
wheals are elicited by stroking or scratching the
skin
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These wheals subside within 30 minutes
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Some patients have chronic dermographism
which may persist throughout life
Angioedema
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Non-pitting subcutaneous swelling
◦ Well demarcated
◦ Distribution
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Face
 Hands
 Buttocks
 Genitalia
 Abdomen
 Laryngeal angioedema (Anaphylaxis)
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Anaphylaxis is a medical emergency
Workup in a patient of Urticaria
Careful History
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Travel and work history
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Ingestion of foods, medications, herbals,
vitamins
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Recent infection
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Negative history makes finding cause more
difficult
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Known allergies
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Family History of allergy or Thyroid disease
Investigations
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Consider brief panel depending on history
i. Hb, CBC
ii. Urine analysis
iii. Stool analysis
iv. ESR
v. Liver Function Tests
vi. TSH
vii. ANA
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Skin biopsy if lesion present >24 hrs, consider
urticarial vasculitis
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Autologous Serum test
Treatment
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Management :
General
◦ Rule out Anaphylaxis
◦ Discontinue offending drugs, food, or behavior
◦ Offer Reassurance
Discuss idiopathic nature of chronic urticaria
Unlikely to identify a specific cause
Contd…
Treatment
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Step 1: Non-Sedating Antihistamines (e.g.
Fexofenadine)
◦ Less effective antipruritic as compared to
sedating Antihistamine
◦ Consider for daytime urticaria symptom control
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Step 2: Sedating Antihistamines (e.g. Hydroxyzine)
◦
Consider for night time and refractory to step 1
◦ Beware of sedation and risk of fall in older
patients
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Step 3: Add H2 Receptor Antagonist (e.g. Ranitidine)
Contd…
Treatment
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Step 4: Other anti-histaminics
◦ Doxepin
◦ Cyproheptadine
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Step 5: Leukotriene modifier
◦ Montelukast
◦ Zafirlukast
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Step 6: Systemic Corticosteroids
◦ Prednisone 20-40 mg PO qd
◦ Caution : Process may flare when steroids are
weaned off
Thank you