15 - Emergency Dermatology Flashcards
What is the essential general management for all dermatological emergencies?
- Full supportive care
- Withdrawal of precipitating agents e.g drugs
- Management of complications
- Specific treatment
What is the difference between urticaria and angiooedema?
Urticaria: Wheals (hives) due to swelling in dermis that raises the epidermis (superficial). They last a few minutes to 24 hours and are often very itchy and can burn
Angioedema: Swelling deeper in the skin or mucous membranes. Involves dermis and subcutaneous tissues. Resolves within 24 hours. Can be itchy but often asymptomatic
What is the pathophysiology of urticaria?
Local increase in permeability of capillaries and small venules due to inflammatory mediator release, usually histamine from mast cells but also prostaglandin and leukotrienes
Release of histamine due to immunological (chronic urticaria) or non-immunological causes (acute urticaria)
If bradykinin is also released with histamine this causes angioedema with the urticaria
What are the different classifications of urticaria and what causes them?
Acute (External factor activates mast cells)
- Allergies to food, medications or animals
- Contact e.g latex, stinging nettles
- Medications
- Viral infections
- Dermatographism
Chronic (Autoantibodies target mast cells)
- Chronic idiopathic urticaria
- Chronic inducible urticaria e.g sunlight, exercise, emotions
- Autoimmune urticaria e.g SLE
Why is acute urticaria dangerous?
If allergic urticaria can turn to anaphylactic shock, asphyxiation and drath
What is the typical distribution of urticaria and angiooedema?
Urticaria: generalised, anywhere on the body
Angiooedema: usually localised to the face (particularly eyelids), hands, feet and genitalia. It may involve tongue, uvula, soft palate, larynx.
How is acute urticaria diagnosed?
- Anyone with history of wheals that resolve within 24 hours with or without angioedema
- Can do skin prick tests or radioallergosorbent tests (RAST) if suspect the cause is a drug/food allergy
How is acute urticaria managed?
- Identify and avoid triggers e.g foods, NSAIDs
- Give non-sedating antihistamine every day for six weeks e.g Cetirizine or Fexofenadine
- If acute severe and has angiooedema give above plus short course of oral corticosteroids e.g prednisolone
- Use fan, cool flannel or calamine lotion to help itch
- If itch affecting sleep give chlorphenamine at night
How is anaphylaxis managed?
- Adrenaline
- Fluids
- Corticosteroids
- Antihistamine
If a patient with acute urticaria has been upped 4 times to the maximum dose of Cetirizine and is still having issues they can be referred to secondary care. What treatment options can secondary care offer?
- Anti-leukotrienes such as montelukast
- Omalizumab, which targets IgE
- Cyclosporine
- Refer to psychologist if chronic
- Consider rheumatology referral if chronic as could be due to SLE or small-vessel cutaneous vasculitis
What is the pathophysiology and presentation of erythema nodosum?
Presentation: Tender red nodules (lumps) usually on both anterior shins. As they resolve they look like bruises.
Pathophysiology: Inflammation of the subcutaneous fat (panniculitis) due to a hypersensitivity reaction
What are the causes of erythema nodosum?
- Idiopathic (50%)
- Chronic diseases e.g IBD, sarcoidosis, lymphoma, leukaemia
- Streptococcal throat infections
- TB
- Pregnancy
- COCP
- Abx containing penicillin
- Sulfasalazine
What investigations are done if you suspect erythema nodosum?
Diagnosis on clincal presentation but do investigations to find a cause
- ESR/CRP: for infection
- FBC: look for haematological malignancy
- Throat swab and antistreptolysin O titre (ASOT)
- CXR: look for TB, sarcoidosis, lymphoma
- Faecal Calprotectin: IBD
How is erythema nodosum managed?
- Find and manage underlying cause
- Reassure will resolve spontaneously usually within 6/52 with rest and NSAIDs
- Oral steroids can help resolve quicker if severe or chronic
- Refer to secondary care if not resolved after 6/52
How does erythema multiforme present and what is the pathophysiology?
Presentation: Widespread, itchy, erythematous rash with target lesions (red rings within larger red rings with darkest red in centre). Mucosal involvement absent or limited to one mucosal surface (lips)
Other symptoms of mild fever, stomatitis, muscle and joint aches, headaches and general flu-like symptoms.
Pathophysiology: Hypersensitivity reaction usually to herpes simplex virus. Can be due to mycoplasma pneumonia
How is erythema multiforme managed?
- If unknown cause need to do CXR for Mycoplasma Pneumoniae
- Usually self-resolves within 1-4 weeks but can recur with coldsores
- If affecting oral mucosa and severe may need IV fluids, analgesia and steroids
What is this?
Erythema Migrans - think Lyme Disease
Eczema can have secondary infections due to breaks in the skins barrier. What are the two main secondary infections that can occur and how do they appear?
S.Aureus Infection: Crusty, oozing rash with associated erythema. Avoid abx if systemically well, just carry on with emollients and steroids
Eczema Herpeticum: Punchout erosions, vesicles, crusted papules all due to Herpes Simplex Virus. Needs immediate hospitalisation