RT Book, Section
A1 Saavedra, Arturo P.
A1 Roh, Ellen K.
A1 Mikailov, Anar
SR Print(0)
ID 1199571182
T1 Skin Signs of Hematologic Disease
T2 Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology, 9e
YR 2023
FD 2023
PB McGraw-Hill Education
PP New York, NY
SN 9781264278015
LK accessmedicine.mhmedical.com/content.aspx?aid=1199571182
RD 2024/04/20
AB Thrombocytopenic  purpura  (TP)  is  characterized  by  cutaneous  hemorrhages  occurring  in  association  with  a  reduced  platelet  count.Occur  at  sites  of  minor  trauma/pressure  (platelet  count  <40,000/μL)  or  spontaneously  (platelet  count  <10,000/μL).Due  to  decreased  platelet  production,  splenic  sequestration,  or  increased  platelet  destruction.Decreased  platelet  production.  Direct  injury  to  bone  marrow,  drugs  (cytosine  arabinoside,  daunorubicin,  cyclophosphamide,  busulfan,  methotrexate,  6-mercaptopurine,  vinca  alkaloids,  thiazide  diuretics,  ethanol,  estrogens),  replacement  of  bone  marrow,  aplastic  anemia,  vitamin  deficiencies,  and  Wiskott–Aldrich  syndrome.Splenic  sequestration.  Splenomegaly  and  hypothermia.Increased  platelet  destruction.  Immunologic:  Autoimmune  TP,  drug  hypersensitivity  (sulfonamides,  quinine,  quinidine,  carbamazepine,  digitoxin,  or  methyldopa),  after  transfusion.  Nonimmunologic:  Infection,  prosthetic  heart  valves,  disseminated  intravascular  coagulation,  and  thrombotic  TP  (microangiopathic  hemolytic  anemia,  thrombocytopenia,  neurologic  abnormalities,  fever  and  renal  disease).Skin  Lesions.Petechiae:  Small  (pinpoint  to  pinhead),  red,  nonblanching  macules  that  are  not  palpable  and  turn  brown  as  they  get  older  (Fig.  20-1);  later  acquiring  a  yellowish-green  tinge.  Ecchymoses:  Black-and-blue  spots;  larger  area  of  hemorrhage.  Vibices:  Linear  hemorrhages  (Fig.  20-1),  due  to  trauma  or  pressure.  Most  common  on  legs  and  upper  trunk,  but  may  occur  anywhere.Mucous  Membranes.Petechiae:  Most  often  on  palate  (Fig.  20-2)  and  gingival  bleeding.General  Examination.  Possible  CNS  and  internal  hemorrhage,  anemia.Laboratory  Hematology.  Thrombocytopenia.Serology.  Rule  out  HIV  disease;  antibodies  against  ADAMTS  13  (a  protease).Lesional  Skin  Biopsy  (bleeding  usually  can  be  controlled  by  suturing  biopsied  site)  to  rule  out  vasculitis.Differential  diagnosis.  Senile  purpura,  purpura  of  scurvy,  progressive  pigmentary  purpura  (Schamberg  disease),  purpura  following  severe  Valsalva  maneuver  (coughing,  vomiting/retching),  traumatic  purpura,  factitial  or  iatrogenic  purpura,  and  vasculitis.Management.  Identify  underlying  cause  and  correct,  if  possible.  Oral  glucocorticoids,  high-dose  IV  immunoglobulins,  or  platelet  transfusion  for  chronic  (Immune  Thrombocytopenic  Purpura)  ITP  (splenectomy  may  be  indicated).