| What are specific questionnares used to diagnose contact dermatitis? | Age, occupation, address, history of contact dermatitis, atopy, stasis, dermatitis, otitis, lichen, psoriasis.
onset of symptoms, pruritis, starting (cosmetics, occupation, hobbies, medications)
Physical exams (hands, perianal, otitis externa, eyelids, ophthalmo, hair, stasis, dermatitis.
Environment (animals, garden, carpet), work, home, cosmetics contact, previous treatment and efficacy. |
| What is patch testing? | Used to determine allergens for allergic contact dermatitis, series of allergens applied to the upper back, removed after 2 days, on day 4-5 patient returns for results, positive reactions show erythema, papules or vesicles.
Identification of specific allergen helps find products free of these allergens, it is the gold std for dx of ACD, indicated for any pt w/acute/chronic pruritic/eczematous or lichenified dermatitis sus of secondary ACD.
If dermatitis is extensive it should be controlled before PT, can't perform it on a lesion already found, stop immunosupressive tx, or lower dose, refrain from sun tanning 2-4 weeks prior to PT, not done for pregnant/breast feeding pt. |
| How is patch test graded? | according to international guidlines (doubtful, weak positive, strong positive, extreme positive, irritant reaction, negative reaction according to lesion)
There are panels that hold different allergens (seen in truetest.com) |
| How is allergen testing? | Not all pt need PT, only if unclear allergen or chronic dermatitis it is needed, positive test is considered only if the rash is gone after removal of allergen.
Allergens causing ACD (nickel (most common), chromates (leather, cement), rubber accelerators, fragrances, preservatives, hair dye, cocoamidopropyl betaine, meds (topical)
Read positive test at 96 hours, to improve rash avoidance of allergens is required
1-3% of population are allergic to cosmetics ingredients |
| What is immediate contact dermatitis? | After exposure to offending topical agent we see contact utricaria with a wheal and flare reaction, most cases are mild but anaphylactic reactions can sometimes occur, some types of contact urticaria include exposure to cold, dermatographism, pressure, exercise, solar, heat, and choline.
Latex allergy may be immediate HS, see burning, stinging, itching w/ or w/out urticaria, may include allergic rhinitis, anaphylaxis (so important to notice it to not wear gloves).
Test is prick test to latex, pt withdraw antihistamine w/out dermographism (anaphylaxis, RAST, skin prick). |
| How is the difference in relevancy of tests? | Tests are considered relevant or not in case of the recent frequent exposure to the allergen or not (example of pt who works in a bakery but used to work w/cement, his cement allergy isn't relevant any more) |
| What is the differential diagnosis of CD? | Atopic dermatitis (early age chronic in nature, family hx)
Seborrheic dermatitis (on scalp, periauricular, face, sharpe demarcated lesions)
Dyshidrotic eczema (hands, symmetrical)
Mycoses fungoides and Cutaneous T cell lymphoma
May see fingertip dermatitis w/ fissures (florist) |
| How is evaluation of contact dermatitis? | Identify possible irritant and avoid, if not improving reffer to dermatologist, patch test performed in occupational cases w/sus chronic irritant dermatitis exclude ACD.
Avoidance (of allergen is key to successful tx, some allergens are cross reactors, we can use special tests to detect presence of metals (Ni, Cr) in products to avoid them |
| How is first line treatment of CD? | Topical corticosteroids, soap substitutes and emollients tx of established contact dermatitis, if infected combined topical corticosteroid + Abx.
Long term intermittent use of mometasone furoate in chronic hand eczema, topical tacrolimus effective in nickel ACD |
| How is second line treatment of CD? | PUVA, azathioprine, methotrexate and ciclosporin are used for steroid-resistant chronic hand dermatitis. Several prospective clinical trials to support these treatments.
Grenz rays (X-rays produced at low
kev, low penetration power) for chronic hand dermatitis showed a significantly better response with this therapy compared with use of topical corticosteroids.
Alitretinoin is an endogenous acts as pan-agonist at retinoid
receptors, binding with high affinity to both retinoic acid receptors and retinoid X receptor
Nickel elimination diets |
| How is ICD prevention done? | Education about irritant avoidance, use personal protective equipment (gloves), use less irritating substances than soap like emollients and soap substitutes, care for months after dermatitis has healed (since skin is vulnerable to flares of dermatitis) |
