Mastocitose Cutânea | Urticaria pigmentosa

Mastocitose
 
Clinical presentation
  • Result of mast cell infiltration or related to the release of mediators in the skin or other affected organs
  • Lesões maculo papulosas podem ser pigmentadas
  • Trauma cutâneo (ex esfregar a pele com a mão) pode causar desgranulacao dos Mastocitos e provocar uma lesão - sinal de Darier
  • May have blisters
 
Exames complementares de diagnóstico
  • Triptase habitualmente elevada nas sistémicas
 
Epidemiologia e Evolução
  • A maioria dos casos (~65-75%) surge na infância, tipicamente antes dos 2 anos de idade
  • Quando na infância tendem a resolver na adolescência. Se não resolverem podem persistir na idade adulta e pode ser necessário fazer um medulograma
 
Tratamento
  • New treatments
    • Imatinib if KIT mutation
    • Omalizumab
 
Geral de todas as mastocitoses (ver mastocitoses):
Histologia
  • Mastócitos têm grânulos metacromáticos que coram com toluidine azul
  • KIT membranar (CD117) é o marcador imunohistoquímico muitas vezes usado
 
DDx
  • Disorders that cause a secondary increase in mast cells
    • Parasitic infections
      • Toxoplasmosis
    • Allergic reactions (urticaria, insect bites)
    • Immunological reactions (GVHD, granulomatous reactions)
    • Benign tumors (hemangioma, neurofibroma)
    • Benign hematological disorders (thrombocytopenia, hypereosinophilic syndrome, porphyrias, Castleman’s disease)
    • Malignant disorders (Hodgkin’s and other lymphomas)
 
Exames complementares
  • Serum triptase
  • Urinary histamine
 
Tratamento
  • Prognosis for mastocytosis in children is almost always favorable. Pigmented urticaria regresses in half of cases around puberty, while congestive manifestations fade around the age of 2 or 3.
  • There is currently no cure
  • Elimintation of mast cell degranulation factors
    • Avoid: general anesthesia, imaging with iodinated contrast agents, medications
    • Introduction of drugs that may induce degranulation of mastcells must be carried out under strict medical supervision with paramedication with antihistamines
    • General anesthesia without precautions or without information from the anesthesiologist is considered high risk in these patients
  • Symptomatic treatment
    • Antihistamines
    • Proton pump inhibitor if peptic ulcer due to gastric histamine release
    • Disodium cromoglycate - mast cell membrane-stabilizer. 800mg/day for adults, 60-100mg/day for children
    • Phototherapy
      • PUVA, UVA1
    • Topical very strong corticosteroids
    • Adrenaline if signs of anaphylatic shock
    • Biphosphonates for bone pain and osteoporosis
  • If aggressive and/or symptomatic
    • Tyrosine kinase inhibitors
      • Imatinib, masitinib, midostaurin
      • Interferon
      • Chemptherapies
      • Allogenic bone marrow transplant