A 22-year-old Thai man presented with skin rash on his legs for 5 days.

• 6 days PTA, he had severe generalized abdominal pain (pain score 8/10) with non-bloody diarrhea. 
• 5 days PTA, he developed skin lesions on both legs, arthritis of the Rt ankle, low-grade fever and started to lose weight for 4 kg.
• The patient was previously completely normal, without an underlying diseases, and denied any current medications.  
• PE:  
  • BT 37.8 C, BP 140/90 mmHg, PR 90/min, RR 18/min 
  • No malar rash, no oral ulcer, no alopecia 
  • Heart normal S1 S2, no murmur 
  • Lungs clear, equal breath sounds, no adventitious sounds 
  • Moderate abdominal tenderness at lower quadrants of abdomen, with no rebound or guarding and no mass, normoactive bowel sounds. 
  • Multiple elevated, firm, hemorrhagic, non-blanchable papules at both legs
  • Mild swelling with tenderness during active and passive motion of Rt ankle 

• Lab:  
  • WBC 5,200 (N 75, L15, Eo1), Hct 39%, Plt 270,000, ESR 72, CRP 22.7 
  • BUN 16, Cr 1.0, TP 7.0, Alb 3.5, TB 1.0, DB 0.6, AST 42, ALT 43, ALP 140
  • UA protein neg, blood neg, WBC 0-1, RBC 0-1
  • HBsAg neg, anti-HCV neg, anti-HIV neg
  • C3 and C4 normal, RF negative, ANA 1:80 fine speckled 
  • Stool examination, CTWA - pending 

Questions:  What is the provisional diagnosis? 

A. Male SLE 

B. IgA vasculitis 

C. Polyarteritis nodosa 

D. Cryoglobulinemic vasculitis 

E. ANCA-associated vasculitis 

โดย น.ท.หญิง อินทิรา  อุไรเลิศ อายุรแพทย์โรคข้อและรูมาติสซั่ม กองอายุรกรรม รพ.ภูมิพลอดุลยเดช กรมแพทย์ทหารอากาศ

ANSWERs

Differential diagnosis

• Male SLE:  The patient did not show common skin manifestations (e.g.malar rash, discoid rash), typical arthritis of small joints of hands, or common clinical of renal involvement of male SLE. In active SLE, C3 and C4 could be low, and patients usually reveal a significantly titer of positive ANA result.
• Polyarteritis nodosa (PAN):  Patients with PAN may present with severe abdominal pain from impending bowel ischemia due to mesenteric vasculitis, however, the skin lesions of small-vessel vasculitis that occured in this patient were not a common feature. More common skin lesions in PAN include erythema nodosum and livedo reticularis. PAN patients may have association with chronic hepatitis B infection. 
• Cryoglobulinemic vasculitis:  The patient's skin lesions were compatible to be found in mixed cryoglobulinemic vasculitis. However, in mixed cryoglobulinemic vasculitis, C4 could be low and RF could be positive and the disease may show association with chronic hepatitis C infection.
• ANCA-associated vasculitis (AAV):  Although LCV and palpable purpura could be the presenting manifestations of AAV, the patient's age group was younger than most AAV patients in the literature, and he did not have other common manifestations of AAV (e.g. glomerulonephritis, chronic sinusitis, allergic rhinitis, asthma, eosinophilia).

The provisional diagnosis is "IgA vasculitis" 

• The skin lesions are compatible with small-vessel vasculitis.
• The patient presented with typical clinical manifestations of IgA vasculitis, including
  • 1) Cutaneous small-vessel vasculitis, predominant at lower extremities 
    • Leucocytoclastic vasculitis (LCV)
    • Palpable purpura 
  • 2) Abdominal pain
    • With or without bloody or non-bloody diarrhea
    • Due to GI vasculitis
  • 3) Arthritis
• Nephropathy could be found in adult patients with IgA vasculitis and patients with certain risks may develop ESRD. However, the clinical was not present in this patient.  
• Investigations when suspecting IgA vasculitis:
  • No specific laboratory results for diagnosis
  • Rising of ESR, CRP
  • Normal C3 and C4
  • Negative ANA and RF
  • Skin or kidney biopsy: florid IgA deposition 

โดย น.ท.หญิง อินทิรา  อุไรเลิศ อายุรแพทย์โรคข้อและรูมาติสซั่ม กองอายุรกรรม รพ.ภูมิพลอดุลยเดช กรมแพทย์ทหารอากาศ