Some of the common differential diagnoses are:
Primary Syphilis:
Primary syphilis presents with one or more sores on the genitals like large round bug bites that are hard and painless.
They heal without treatment in about six weeks.
Urinary Tract Infection:
Usually presents as increased frequency of urination, burning, dysuria, and fever with chills.
There are however no lesions on the genitals.
Ingrown Or Infected Hair Follicles:
Small areas of redness and tenderness develop around the hair follicle, which later develops into pustules and eventually form scabs.
There is no fever or blister formation.
These are characterized by inflammation with itching, irritation and vaginal discharge.
There are usually no lesions on or around the genitals.
Abrasions, lesions due to violent sex, piles, insect bites and many more, which can be differentiated by eliciting the triggering cause of the ailment.
