3.1 Abdomen
Case - Dermatology
I. Urticaria and Pruritus
1. Urticaria
- Definition
- Urticaria: transient appearance of smooth elevated erythematous plaques due to
a vascular reaction ; accompanied by pruritus
- Acute: resolves within hours/days, self limiting, can be recurrent
- Chronic: recurrent episodes lasting >6 weeks
- Often isolated event
- Causes:
- Isolated event
- Idiopathic
- Immune mediated: hypersensitivity reactions I, II or III (allergies, contact)
- Complement mediated: viral/bacterial infections, serum sickness, transfusion
reactions, drug reactions, radiocontrast agents
- Physical: immediate/delayed pressure, contact urticaria, cold urticaria,
cholinergic urticaria
- Pathology
- Mast cell and basophils: release of histamine, bradykinin, leukotriene C4
prostaglandin D2, vasoactive substances
- Histamine: causes pruritus
- Extravasation of plasma into dermis => urticarial lesion
- Clinical Features
- History: precipitants, medical/family history
- Differential Diagnosis
- Dermatological: atopic contact dermatitis, atopic dermatitis, urticarial vasculitis
- Diagnostics
- P.E: angioedema, painful/long lasting urticarial lesions, systemic signs/symptoms,
scleral icterus, hepatic enlargement/tenderness, thyromegaly,
pneumonia/bronchospasm, signs of fungal infection
- Lab (chronic): CBC, ESR, TSH, ANA (antinuclear antibody)
- Other: imaging, punch biopsy
- Therapy
- Pharmacological:
- symptomatic treatment with antihistamines
- Other: omalizumab, glucocorticoids
- Other: avoidance
, 2. Pruritus
- Definition: skin itching due to a dermatological or systemic disease
- Clinical Features
- Risk factors: age, chronic/generalized pruritus, abnormal physical findings
- Diagnostics
- Initial: CBC, TSH, fasting glucose, alkaline phosphatase, bilirubin, creatinine,
blood urea nitrogen
- Extra: radiography (lymphoma)
- Differential Diagnosis
- Dermatological causes
- Systemic:
- Autoimmune
- neurological
- Hematological: iron deficiency anemia
- Hepatobiliary: biliary cirrhosis, chronic pancreatitis with biliary tract
obstruction, cholestasis, hepatitis (esp. C)
- Infectious: AIDS, hepatitis, parasitic (giardia lamblia)
- Malignancy
- Endocrine: chronic renal disease, diabetes, hyper/hypo(para)thyroidism
- Other: rapid weight loss, pregnancy
- Treatment
- Antihistamines: for histamine-mediated pruritus
- Other: Maintain moisture of skin, avoidance
3. Link to the Abdomen
- Infectious
- Hepatitis (A, B, C)
- Urticaria:
- prodromic stages of Hep infection ; pre-icteric symptoms
- Immune complex deposits ; decreased complement levels
- Pruritus
- Helicobacter pylori infection: studies show association with urticaria
- Endocrine
- Pregnancy
- Pruritic Urticarial Papules and Plaques
- Estrogen increase histamine release from mast cells and basophils ->
increased sensitivity to different pathogens ; fragility of skin to
itching/scratching leads to urticaria
- Diabetes Mellitus
- Urticaria:
