Urticaria and angio-oedema

Transcription

1 13 of Allergy Urticaria and angio-oedema Mr Brown is 41 years old. He is an economic analyst. His wife is a tax lawyer. They do not have children. He has come to see to see Dr Do-a-lot on account of a rash that he has developed over the past few months. He describes the rash as raised, red itchy wheals (hives) that appear unexpectedly, mostly on his abdomen, upper thighs and upper arms. They seem to change shape and migrate. They last for a few hours at a time before disappearing spontaneously. At first the symptoms were mild, shortlived and localised to two small patches on either side of his abdomen. Over a period of 3 months the symptoms have increased in severity and frequency to such a degree that they are interfering with his work, his exercise regimen, his relationship with his wife and his sleep. He is at his wits end. He has been working very hard over the past few months on a presentation which he has to give in Europe in 2 weeks time. Last week, on the morning that he was due to present the draft to his local team, he awoke to find that the left side of his lower lip had swelled enormously, as if he had been stung by a bee. He was unable to give his presentation. He took a large dose of antihistamine on the advice of his doctor and the swelling settled slowly over a period of 2 days. He cannot afford a repeat attack when he has to represent his office at the international summit. He has been referred for investigation. The rash is unpredictable. He has cut out spicy foods, milk, alcohol, wheat and coffee to no avail. He is loath to take a warm shower and has stopped mountain biking as it seems worse with heat and exercise. He has tried some of his wife s antihistamines on occasion and he finds that this eases the symptoms. He has never had any kind of allergic disease before. Shaunagh Emanuel, MB ChB The Asthma Clinic, Rondebosch, Cape Town, South Africa Di Hawarden, MB ChB Allergy Diagnostic and Clinical Research Unit, UCT Lung Institute, Mowbray, Cape Town, South Africa References 1. Green RJ, Motala C, Potter PC. ALLSA Handbook of Practical Allergy, 3rd ed. Cape Town: ALLSA, Kaplan AP. Chronic urticaria and angioedema. N Engl J Med 2002;346: Current Allergy & Clinical Immunology, March 2013 Vol 26, No.1 31

2 Dr Do-a-lot asks about when the rash first started, about how long the wheals last and when they appear, what they look like exactly and how long they take to disappear. She asks if they are itchy. She asks many things including questions about family history, illnesses, drugs, allergies, food, smoking, work, hobbies, stress and quality of life. She carefully examines Mr Brown, looking for any signs of systemic illness. She draws a blood sample and requests a FBC (full blood count) and ESR (erythrocyte sedimentation rate), along with a thyroid auto-antibody test. Mr Brown goes home with a script for high doses of antihistamines which he has been instructed to take two to three times per day until he returns for his blood results. Dr Do-a-lot decides to discuss urticaria and angio-oedema with her students for their next tutorial. Dr Do-a-lot tells her students that urticaria is often as confusing and frustrating for doctors as it is for patients. She shows her students a simplified diagnostic algorithm that she uses to assist her in making a diagnosis. Then she asks the students to research aspects of the algorithm. They report back the following week. Urticaria: simplified diagnostic algorithm 32 Current Allergy & Clinical Immunology, March 2013 Vol 26, No.1

3 Urticaria is characterised by the rapid appearance of wheals which have three typical features: central swelling of variable size surrounded by a reflex erythema; associated itching or sometimes burning but no pain; fleeting in nature with a return to normal in 1-24 hours. The lesion is superficial and tends to migrate. Angio-oedema is defined by a sudden, pronounced swelling of the lower dermis and subcutis; sometimes associated with pain rather than itch, with frequent involvement of the mucous membranes and a slower resolution in up to 72 hours. Usually the lips, periorbital area, hands, feet and genitalia are affected. The tongue and oropharynx may be involved, but almost never the larynx. Mast cells and basophils in the skin release inflammatory mediators including HISTAMINE which causes vasodilatation and increased capillary permeability resulting in the raised red lesions of urticaria. There are many mechanisms and molecules which can cause mast cell degranulation. In chronic urticaria and angio-oedema the cause is seldom IgE. Chronic urticaria is urticaria that has been present for longer than 6 weeks and the cause is often not found. If it is not a physical urticaria, it is usually chronic idiopathic urticaria or autoimmune urticaria. Acute urticaria is urticaria that is present for less than 6 weeks. It is often IgEmediated. Consider drugs, food and insects. It may be non-ige-mediated. Causes may include the following: infections like sinusitis, viral hepatitis, Candida, and infectious mononucleosis or Helicobacter pylori; serum sickness from a blood transfusion; drugs or viral infection with associated systemic symptoms; direct mast cell activation by some drugs like morphine and non-steroidal antiinflammatory drugs (NSAIDs); non-allergic food reactions including salicylates, azo dye food colourants, benzoate preservatives; histamine from scombroid toxin in fish. There is often a temporal relationship with the causative agent and the trigger may be evident on history. Anaphylaxis is not common but be aware of the possibility in bee stings, parenteral antibiotics and peanuts. Urticaria affects 15-25% of people at least once in their lifetime. It is twice as frequent in women. Possible triggers for urticaria include stress or emotion, heat, hormones, infections, foods and drugs. Current Allergy & Clinical Immunology, March 2013 Vol 26, No.1 33

4 When taking a history in a patient with urticaria, important questions to ask include: Time of onset of disease Frequency and duration of wheals Diurnal variation Shape, size, distribution Associated angio-oedema Itch or pain Family history of same Allergies or internal diseases Induction by physical agents or exercise Use of drugs: NSAIDs, hormones, laxatives, drops, immunisations Food Smoking Type of work Hobbies Relation to weekends and holidays Surgical implantations Reaction to insect stings Relation to menstrual cycle Response to therapy Stress Quality of life related to urticaria Types of physical urticaria Dermographic skin writing Delayed pressure shoes and bra straps Cold contact warming after cold Heat contact local heat Solar sunlight Vibratory jackhammer Special types of urticaria Cholinergic sweating Adrenergic adrenaline Contact absorbed through skin Aquagenic reaction to water Important causes of urticarial-type rash Urticaria pigmentosa (mastocytosis) Urticarial vasculitis Familial cold urticaria (a vasculitis) Consider these if: Lesions last >24 hrs Pain rather than itch Bruising or scarring after lesions Arthralgia or arthritis Constitutional symptoms Lack of response to antihistamines 34 Current Allergy & Clinical Immunology, March 2013 Vol 26, No.1

5 Special investigations are usually few if any at all They might include: FBC, chemistry and urine tests are usually normal Thyroid functions, antithyroglobulin, antimicrosomal antibodies may be useful ESR, antinuclear antibody (ANA) if connective tissue disease is suspected C4 and C1 inhibitor function in angio-oedema alone Food allergy testing only in rare cases where history is suggestive Skin biopsy in suspected vasculitis Note: Always be careful to exclude systemic conditions including connective tissue diseases like systemic lupus erythematosis (SLE), vasculitis and thyroiditis. Non-drug treatment Reduce triggers, e.g. heat, stress or alcohol. Avoid medications (e.g. NSAIDs, opiates, ACE inhibitors) if implicated. Reduce specific physical stimuli like rubbing, pressure or cold. Manage diet only if specifically indicated. Treat any known causes. Cooling lotions may be helpful. Be emotionally supportive. Develop a partnership with the patient in the management of a long-term condition that can have far-reaching emotional, social and physical effects. Spend time explaining the pathogenesis and why and how the medication can be used as a tool to control the condition. Tell them what to expect: half of the patients are better in a year, some continue to be symptomatic for as long as 5 years and some follow a remitting and relapsing course. Drug treatment First line: high doses of long-acting, secondgeneration antihistamines. Short courses of glucocorticosteroids may be used for exacerbations. Cyclosporin (2 mg/kg bd in reducing doses over 3 months) may be used with caution in severe cases. It has a high side-effect profile and patients should be referred to a specialist centre. Mr Brown had a normal FBC and ESR and no other cause was found to explain his chronic urticaria. His initial dose of fexofenadine 180 mg three times daily was decreased to a twice-daily dose after a few weeks as he responded well to treatment. He flew to Brussels where he delivered his report without the impediment of swelling or itch. He is eating a healthy balanced diet, and has resumed mountain biking. He keeps antihistamines with him as he finds that on occasion, when he becomes stressed at work, he develops a few wheals on his abdomen, and requires an extra dose. He has learned to use his medication to control his symptoms. He is working on controlling his response to stress. Current Allergy & Clinical Immunology, March 2013 Vol 26, No.1 35