urticaria final

7/30/2019 Urticaria Final

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URTICARIA Commonly referred to as hives, is a kind

of skin rash notable for pale red, raised,

itchy bumps. Hives are frequently caused

by allergic reactions



Urticaria - Causes

The majority of chronic hives cases have

an unknown (idiopathic).

Acute viral infection is another common

cause of acute urticaria (viral exanthem)

Less common causes of hives include

friction, pressure, temperature extremes,

exercise, and sunlight.



APPEARANCE OF

SYMPTOMS Wheals (raised areas surroundedby a red base) from urticaria canappear anywhere on the surface of

the skin. Wheals may be pinpoint in size, orseveral inches in diameter.Fluid leakage from superficialblood vessels



Immunologic Mechanism:

(A) Type I -HYPERSENSITIVITY REACTION.(B) Type III- HYPERSENSITIVITY REACTION.

Non Immunologic Mechanism

(a) direct effect(b) effect on archidonic acid metabolism-

Leukotrien B4(C) idiopathic or undetermined



CLASSIFICATION 1.Acute Urticaria.

Presence of evanescent wheals which completely

resolve within six weeks.

2.Chronic urticaria (ordinary urticaria)

Presence of evanescent wheals which persist

for greater than six weeks.



Food item: Spicy food, Egg, Fish, Strawberry even milk and it product.

Drug: Aspirin, Certain Antibiotics, NSAID. ,Codeine ,

Morphine.

Inhalants :- Pollen - Spore – House Dust Mite.

INFECTION AND INFESTATION:

Psychological factor play important role

Certain systemic diseases : Malignancy [lymphoma ]

endocrine.

Diseases as [thyrotoxicosis . polycythemia] , Liver

Disease, Pregnancy



Drug-induced urticaria

Urticaria by infection orenvironmental agent

Dermatographic urticaria

Pressure or delayed pressure

Classification By Cause



Classification …

Chronic cold urticaria

Solar urticaria

Water-induced urticaria

Exercise urticaria



Investigations

General : CBP , ESR, GSE, GUE, urine and bloodsugar, liver and renal function tests.

Skin test: commonly used in patient with chronicurticaria.

Certain disease commonly associated withchronic urticaria as sinus infection, UTI,hyperthyroidism, intestinal warms, internalmalignancy, lymphoma, pregnancy and chronicexposure to external allergen.



It can be difficult to determine appropriatemedications, since some, such as loratadine, require aday or two to build up to effective levels, and thecondition is intermittent and outbreaks typically clear upwithout any treatment.

Treatment plans for urticaria involve being aware of

one's triggers

Antihistamines such as diphenhydramine may beused.

MANAGEMENT



H1-H2 Receptor Antagonists

85/15 ratio of skin H1/H2 receptors

Combination of anti H1&2 providesadditional treatment benefit

Doxepin blocks both receptors andis a more potent anti-H1 blocker thandiphenhydramine or hydroxizine

Sedation may limit usefulness ofdoxepin



Zafirlukast and montelukast superior to placebo

in treatment of chronic urticaria.

Have not been compared to therapy withantihistamines.

No additional effect once maximal antihistamineeffect achieved.



Oral sympathomimetics (e.g., terbutaline) studied to reduce

erythema / swelling

Side effects substantial (insomnia, tachycardia)

Efficacy low

SYMPATHOMIMETIC

AGENTS



CORTICOSTEROIDS

Indicated when inadequate response tohistamine receptor blockers and leukotrienereceptor antagonists

Effective but with substantial side effects

Alternate day therapy if must be used

One approach – start 15-20 mg qod andtaper to 2.5-5mg q three weeks, d/c after 4-5months



Experimental

Therapies

Cyclosporine at low doses (2.5-3 mg/kg) effective andsteroid sparing

High dose (6 mg/kg) very effective but with severe sideeffects

Other agents less well studied include sulfasalazine,

hydroxychloroquine and dapsone, IV IgG

Plasmapheresis for patients with anti-IgE Ab effective butimpractical for long-term treatment



Recommendations

Laboratory workup rarely necessary (except thyroidevaluation)

Antihistamines mainstay of therapy (H1and H2)

Nonsedating at low/high doses effective for mild/moderatedisease

Older, sedating antihistamines more effective for severeurticaria and/or angioedema

Minimize systemic corticosteroids (alternate day)



Contact DermatitisIt is a term for a skin reaction (dermatitis) resulting

from exposure to allergens (allergic contact dermatitis)or irritants (irritant contact dermatitis).

Phototoxic dermatitis occurs when the allergen orirritant is activated by sunlight.



Symptoms

Localized rash or irritation of the skin caused by contactwith a foreign substance.

Only the superficial regions of the skin are affected incontact dermatitis.

Contact dermatitis results in large, burning, and itchy rashes,and these can take anywhere from several days to weeks toheal.



Causes

The most common causes of allergic contactdermatitis a

The alkyl resorcinols in Grevillea banksii andGrevillea 'Robyn Gordon' are responsible forcontact dermatitis re plants of theToxicodendron genus.

Other common causes of irritant contactdermatitis are harsh (highly alkaline) soaps,detergents, and cleaning products.



Classification

Irritant contact dermatitis

Allergic contact dermatitis

Photocontact dermatitis



Self-care at home.

Immediately after exposure to a known allergen or irritant,wash with soap and cool water to remove or inactivate

most of the offending substance.

Medical care

Corticosteroids.

Antihistamines.

urticaria final

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