hi I have a rash each time I swim

Dear Customer
Welcome, and thank you for trusting us
Regarding your question

how to treat skin allergy after swimming ?

If there is itching and wide space of skin rash in this case you need to use dexamethasone injection and also you need to use topical hydrocortisone 1%
I also recommend to use antihistamine medications like fexodine120mg to ease symptoms.
If rash lasts you need to consult dermatologist to help you and to follow up treatment.

How to diagnose the cause of skin rash?

There are many causes and those include:
Allergy,
Dermatological disease
Side effects of drugs
Systemic illness
Local infection
 

what tests should you do ?

CBC
ESR
AST
ALT
CREATININ
CRP
 
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