patho help - IgE

my head is killing me and I can't think straight right now. any assistance would be appreciated.

E. O. is an 8-year-old girl with a history of asthma and allergy to bee stings. She has been brought to the clinic with a throat infection. She was treated one time previously with a penicillin antibiotic and developed a slight rash, but no other side effects. Her health-care provider prescribes a course of penicillin to treat her current infection and cautions her parents to watch her closely for a reaction.

1. What type of reaction is the health-care provider concerned about and why?

The provider is concerned about an IgE mediated allergic reaction. E.O. was previously administered penicillin and had a mild immune response to the drug. Reexposure to the drug may cause an increased allergic reaction, possibly anaphylaxis because her body has already created IgE specific to penicillin.

2. Explain the role of IgE and mast cells in this type of hypersensitivity reaction.

Initial exposure to an antigen causes B lymphocytes to produce IgE which coat the surface of the mast cell by binding to Fc receptors on the cell. Subsequent exposure to the same antigen cross links the IgE and causes degranulation of the mast cell and release of mast cell products. The products such as histamine and serotonin cause rapid constriction of the vessels causing the hypersensitive reaction.

3. Why might E. O. react adversely to the antibiotic this time when she did not before?

Previously E.O. had not developed the IgE immunoglobulin to penicillin. Now that the IgE is available she will possibly have a heightened reaction to the drug.

4. What would you teach her parents to look for when assessing for a reaction?

itching, angioedema, edema of larynx, uticaria, bronchospasms, vomiting, abdominal cramps, diarrhea.

5. What would you suggest the parents do if a reaction does occur?

Call 911, administer epinephrine if available.

I feel like I am missing something important and am not making any sense. help?