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How to examine for Spider Naevus an OSCE guide

Spider Naevus is a sign of liver cell failure.Sometime seen in healthy Individuals also.
1. Ask the patient to adequately expose.
2. Examine the- face. neck, arms and chest above the nipples
3. Blanch the spider naevus using the head of a pin or a glass slide.          
4. Release pressure to look for flushing.
5. Comment as present or not.
If present, significant or not significant.
Note the following
  • Count the naevi above the level of the nipples i.e. in the drainage area of the superior vena cava.
  • Less than 7 spider naevi are normal in young persons
  • More than 7 occur in liver cell failure pregnancy  or in persons on oral contraceptive
  • Spider naevus occurs because of the dilatation of a central arteriole (the body of the spider) which feeds the vessels radiating from it (the legs of the spider). If a red naevus does not blanch, it is purpura. Blanching occurs fully in erythema also and partially in telanglectasias.

These steps are very important for students preparing for USMLE and MRCP exams