Photobiology, Photodermatoses and Sunscreen Flashcards
What is the most common skin disorder provoked by sun exposure
Polymorphic Light Eruption (PMLE)
What skin disorders can be diagnosed by photoprovocation?
List 3
- Polymorphic Light Eruption (PMLE)
- Actinic prurigo
- Actinic folliculitis
- Solar urticaria
- Chronic actinic dermatitis
- Juvenile spring eruption
- Hydroa vacciniforme
What lab investigations should be performed to evaluate photodermatoses?
List 3
- ANA
- ENA
- dsDNA
- Porphyria screen (feces, RBCs, urine)
What are photopatch testings performed for?
Suspected contact dermatitis to a substance occurring onliy in the presence of sunlight (sunscreen/NSAIDs)
List 3 benefits of UV
- Production of Vitamin D (moderate exposure)
- Regulates calcium metabolism, insulin secretion, BP, immunity and cell propagation
- Improvement in mood
- Increase in energy
- Treatment of dermatological conditions
- Inflammatory skin conditions
- Vitiligo
- CTCL
- Granuloma annulare
What is a photosensitizer?
A chemical or drug that induces a photodermatosis
What is a photodermatosis called that is eczematous?
Photodermiatitis
What is a phototoxic reaction?
Exaggerated sunburn-like reaction without an immune response due to a drug or chemical
What is a photo exacerbated reaction?
List 5 examples.
An underlying skin condition worsening due to UV light
- Lupus erythematosus
- Dermatomyositis
- Darier disease
- Rosacea
- Pemphigus vulgaris
- Pemphigus foliaceus
- Atopic dermatitis
- Psoriasis
List 5 clues of photosensitivity
- Exacerbated in summer
- Sharp cut-off between affected area and skin covered by clothing/jewelry
- Sparing of:
- Folds of upper eyelids
- Deep furrows on face/neck
- Skin covered by hair
- Skin shadowed by ears, under nose and under chin
- Sparing of web spaces between fingers
List 3 phototoxic/allergic reactions caused by external photosensitizers
- Drug-induced photosensitivity
- Thiazides
- Tetracyclines
- NSAIDs
- Phenothiazines
- Voriconazole
- Quinine
- Vemurafenib (EGFRi)
- Photocontact dermatitis
- Due to phototoxic chemicals
- Psoralens in plants, vegetables, fruit
- Fragrances in cosmetics
- Sunscreen chemicals
- Dyes and disinfectants
- Due to phototoxic chemicals
- Pseudoporphyria
- Induced by drugs +/- renal insufficiency
List 2 genetic photodermatoses
- Xeroderma pigmentosum
- defect in DNA repair
- Bloom syndrome
- Autosomal recessive
- Short stature
- Telangiectasia
- Rothmund Thomson syndrome
- Autosomal recessive
- Poikiloderma
- Cockayne syndrome
- Autosomal recessive
- Neurodegenerative disorder
What is the most common form of porphyria?
What causes porphyria?
What systems are affected by porphyria?
Porphyria cutanea tarda
Impairment in the process that makes heme
- Cutaneous - blistering, scarring, photodermatitis
- GI - Abdominal pain/cramping, vomiting, constipation
- CNS - seizures, mental disturbances, nerve damage
- MSK - muscle pain, weakness or paralysis
- GU - urine can turn red/brown
Name this dermatological diagnosis
Polymorphic light eruption (PMLE)
Who is typically most affected by polymorphic drug eruption (PMLE)?
What type of reaction is PMLE?
How to prevent PMLE?
Young, adult women (20-40s)
Delayed hypersensitivity reaction to a compound in the skin altered by exposure to UV radiation
- Cover affected areas with UPF clothing or densely woven sun protective clothing
- Stay in the shade
- Apply SPF 50 frequently to all uncovered skin
- Fake tan (SPF 2)
- UVB desensitization
- Emergency oral steroids (5 days)/topical steroids for flare while on holiday
- Antihistamines pre exposure
- Slow introduction to UV exposure in spring/summer months