FACTS ON FINGER TIPS (MIMS)

 2. URTICARIA                                             

     Salient Features

Epidemiology

1. A common condition, affecting 15-20 % of the population at some times in their lives

Aetiology

1. Idiopathic in most cases
2. Physical causes include pressure, changes in temperature excecise, emotions
3. Foods such as some fruits, sea food, nuts and dairy produce are common culprits.
4. Drugs including antibiotics, opioid analgesics and NSAIDs
5. Viral infections
6. Wasp or bee stings
7. Vasculitic causes.
8. Other causes include radio contrast media, blood products, hepatitis B and hereditary angio-edema

Clinical features

1. Transcient, pruritic, oedematous, erythematous rash.
2. Typically blanches on pressure
3. Individual weals resolve within 24hours but may recur at the same or different sites
4. If deeper dermal or sub-dermal tissues are involved, this is referred to as angio-oedema

Investigations

1. Consider skin prick test or serum specific 1gE RAST if foods suspected
2. C3 and C4 complement tests to exclude hereditary angio-oedema
3. Full blood count, ESR, C-reactive protein if vasculitis suspected
4. Liver Function Tests and Hepatitis serology

Management

1. Identity and avoid triggers, if possible.
2. Systemic antihistamines
3. Short courses of oral steroids may be required

Key Points

1. Biopsy lesions if urticarial vasculitis is suspected when weals last more than 24 hours or leave bruising.
2. Chronic urticaria, defined as daily or almost daily weals for at least six weeks, causes severe morbidity

12.DISORDERS AND/OR ADVERSE REACTIONS - ALLERGY - SUMMARY

Refer - Other Information

Contents

1.Evidence Based Medicin

2.Facts on Finger Tips                                                                                                           i.Hay Fever                                                                                                                           ii.Urticaria

3.Disorders and/or Adverse Reactions                                                                              Items   1 to  3

FACTS ON FINGER TIPS (MIMS)

 1. HAY FEVER                                               

     Salient Features

Definition    

1. Symptom complex resulting from an allergic inflammatory reaction to pollen
2. 2. Also sometimes known as seasonal rhinitis

Epidemiology

1. Affects about one in five of the population at some time during the year
2. Prevalence is increasing

Pathophysiology

1. Type I IgE -mediated hypersensitivity to pollen, especially from trees, grass and moulds
2. Often described as being like a curtain falling over the eye

Clinical features

1. Itching, running or blocked nose and sneezing
2. Itchy red eyes and conjunctivitis injection
3. Sometimes itch affects the palate or ear canals
4. Nasal examination reveals a pale blue boggy nasal mucosa

Diagnosis

1. Usually diagnosed on history and examination
2. If diagnosis is uncertain, skin-prick tests or serum -specific RAST may be useful

Management

1. Avoid pollen by wearing sun glasses, keep windows shut and avoid going to fields and grassland.
2. Antihistamines for mild disease
3. Topical nasal corticosteroids, and topical mast cell stabilisers for ocular symptoms
4. Severe exacerbations may require short courses of oral steroids, such as 20mg prednisolone for five days.
5. Consider immunotherapy in severe cases

Key Points

1. Causes significant morbidity that is frequently under-estimated by non-sufferers
2. Avoid sedating antihistamines if possible
3. Topical nasal corticosteroids work better if begun shortly before the relevant pollen season
4. Combination of antihistamines and nasal corticosteroids usually controls symptoms
5. Depot steroid injection is best avoided because of risk of adverse events

12. DISORDERS AND/OR ADVERSE DRUG REACTIONS - ALLERGY - SUMMARY

( Ref- Harrisons - Priniciples of Internal Medicine Ninth Edition )

1. Anaphylaxis (343)
2. Urticaria and Angioedema (344)
3. Allergic Rhinitis (345)

1. Anaphylaxis (343)

The life -threatening anaphylactic response of a sensitized human appears within minutes after administration of specific antigen and is manifested by respiratory distress often followed by vascular collapse, or shock without antecedent respiratory difficulty. Cutaneous manifestations exemplified by pruritus and urticaria with or without angioedema are characterstic of such systemic anaphylactic reactions

2. Urticaria and Angioedema (344)

Uticaria and angioedema may appear separately or together as cutaneous manifestations of
localized nonpitting edema , a similar process may occur at mucosal surfaces of the upper
respiratory or gastrointestinal tract.

Urticaria involves only the superficial portion of the dermis presenting a well- circumscribed
wheals with erythematous raised serpiginous borders with blanched centers which colaese
to become giant wheals.

Angioedema is a well demarcated localized edema involving the deeper layers of the skin
inculding the subcutaneous tissue. Recurrent episodes of urticaria and/or angioedema  of less than 6 weeks duration are considered acute, while attacks persisting beyond this period are designated chronic. 

3. Allergic Rhinitis (345)

Allergic rhinitis is characterized by sneezing, rhinorrhea, obstruction of the nasal passages,
conjuntivial and pharyngeal itching, and lacrimation. Although commonly seasonal owing to
its relation to airborne pollens, other patterns and etiogies occur. The use of the term - hay fever- to decribe seasonal allergic rhinitis is a common convention but is literally inapproiate because the symptom complex is neither producd by hay nor associated with fever.