I work in a nursing home and occasionally see a light browning red discoloration of the skin in the perineum that is not rashy nor does it fade/grow/or change with tx of antifungals/hydocortisones or plain moisture barriers. Is it common
for the perineum to be darker than the rest of the body, and if some of your ancestors were perhaps quite dark-skinned, then it wouldn't be surprising if this made your genitals rather darker.
The changes in the colour of skin of genitalia from puberty
cruris, friction of undergarments and above 40s due to acanthosis nigricans. Acanthosis nigricans may have association with obesity, or endocrine disorders like diabetes mellitus, rarely due to underlying malignancy.
It is true that fungi such as Pityrosporon can darken the skin. However, it wouldn't make any sense to treat yourself with an anti-fungal medication when no proper diagnosis has been made.
The obvious thing to do now is to ask your GP to look at your perineum, and to decide whether you really do have a fungal infection.
It would be advisable to consult a skin specialist for your symptoms and a proper clinical examination.
Let us know if you need any other information and post us on how you are doing.