Have you googled MTX and vasculitis?
What is the time span from taking MTX and the onset of symptoms?
Can you share the time span as to what other meds, including the pediasure, any over the counter meds or herbs, homeopathic meds etc. and the onset of symptoms?
There is a website that you can go to and list all the meds, including what is in the pediasure, and it will let you know if there are any possible reactions between all the meds.
www.drugs.com
Forgive me if I've listed things your son does not take. I'm only trying to help you sort some of this out. The symptoms must be scarry for you and your family.
David is right that MTX is a treatment for vasculitis.
Below is a website I located with some interesting information that indicates MTX can actually cause vasculitis:
http://www.ncbi.nlm.nih.gov/pubmed/9552765
Leukocytoclastic vasculitis induced by low-dose methotrexate: in vitro evidence for an immunologic mechanism.
Halevy S, Giryes H, Avinoach I, Livni E, Sukenik S.
SourceDepartment of Dermatology, Soroka, Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
[email protected]
Abstract
The rare occurrence of methotrexate (MTX)-induced vasculitis has been associated mainly with high or intermediate MTX doses. We report herein a case of cutaneous leukocytoclastic vasculitis (LCV) following treatment with low-dose oral MTX (7.5 mg/week) for rheumatoid arthritis. The histological findings of a cutaneous lesion were consistent with drug-induced vasculitis. The clinical and histological findings, including the temporal relationship between MTX intake and the onset of vasculitis, and the results of withdrawal and rechallenge tests, suggest a causal relationship, and indicate a drug-induced LCV due to MTX. The role of MTX in the induction of the vasculitis was further supported by a positive mast cell degranulation (MCD) test.
FYI - Cutaneous leukocytoclastic vasculitis (CLV) is a necrotizing inflammatory disease of the small vessels in the dermis
This website has photos that may be similar to what you are describing it covers:
Allergic vasculitis Vasculitis - allergic; Hypersensitivity vasculitis; Cutaneous leukocytoclastic vasculitis
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001877/
The two links below are what google list for the search I typed in.
http://www.google.com/search?q=cutaneous+leukocytoclastic+vasculitis&sourceid=ie7&rls=com.microsoft:en-us:IE-Address&ie=&oe=
http://www.google.com/search?q=mtx+%2B+vasculitis&sourceid=ie7&rls=com.microsoft:en-us:IE-Address&ie=&oe=
Good luck. Keep us posted as to what you find out. I don't know if I've listed anything that will be helpful to you.
Your family is in my prayers. Naturelover