Brief Answer:
Kindly, post the image of the lesion.

Detailed Answer:
Hello,
Thanks for posting your query on HealthcareMagic.

Kindly, check whether there is accumulation of smegma beneath the frenulum.
If smegma is present, kindly clean it.
Smegma accumulation can lead to itching and infection.
A bubble/ blister forming on the penis suggests a primary skin lesion rather than fungal infection.
Please post an image of the lesion for better assessment.

Thanks
Dr Shailja P Wahal

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Brief Answer:
Herpes simplex or bullous lesion.

Detailed Answer:
Hello and welcome again,

Blisters are associated with skin lesions called bullous lesions.
Herpes simplex infection is one of sexually transmitted disease (STD) associated with formation of vesicles or blisters which are itchy.
Other STDs and infections are not associated with formation of blisters or vesicles.
Thus, the first step is to rule out herpes simplex infection.
A clinical assessment and a serological test is required to rule out herpes simplex infection.
Abstain from unprotected sexual activity before a diagnosis is made.
Do not use any anti-fungal preparation till the condition is diagnosed since it can have deleterious effect in case the infection turns out to be fungal.
Once herpes simplex infection is ruled out, primary skin lesion called bullous lesion has to be ruled out.

Consult a dermatologist for further work up.

Thanks and take care
Dr Shailja P Wahal

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