Welcome to JustAnswer and thank you for your question.Well, most of the re-occurring cold sores are caused by herpes simplex virus type 1 strain- HSV-1 Infected saliva is also a means of spreading the virus. When a person has active blister-like sores inside nose, at this time he/she is most contagious. And when the blisters have dried and crusted over, then the risk of contagion is significantly lessened.Swab culture test should be done in lab for diagnosis. Viral culture and polymerase chain reaction (PCR) test has to be done for diagnosis.The line of treatment is-Prescription-strength topical medications like- Acyclovir (Zovirax 5% cream) or penciclovir (Denavir 1% cream) FDA-approved medication for cold sore is- acyclovir (Zovirax), valacyclovir (Valtrex), and Famciclovir (Famvir).It helps in decreasing the duration of the outbreak, and prevents the frequent re-occurrence of cold sores. Also cold compresses may relieve pain temporarily. You should wash your hands often, especially after touching the face.A clinical examination is necessary for diagnosis. Medications will be prescribed after clinical evaluation.
Please make an appointment with doctor for management of this issue.
Good luck and take care.
MRSA is caused by Staphylococcus aureus, it is diagnosed with swab culture test. Yes, MRSA can effect nose, and may look like nasal cold sores.MRSA are resistant to many drugs, your doctor can advise- antibiotics vancomycin and teicoplanin (Targocid).
Topical application of an antibiotic ointment such as mupirocin or fusidic acid to the nostrils, 2-3 times per day for 3-5 days can be done. It is important to check for herpes virus inside the nose, as herpes simplex virus type 1 strain- HSV-1 can cause cold sore, and it is treated with anti-viral drugs.