Is there anyone who needs to be extra cautious when it comes to microneedling?

Some people, like with other cosmeceutical treatments, will need to take extra care. Some medical problems prevent persons from safely doing microneedling, or require that microneedling be cleared by a medical expert before proceeding.
These are some of the conditions:

Abnormal skin conditions -If you have atypical skin problems (such as cold sores (Herpes Simplex virus), bruised skin, eczema, rosacea, infectious skin diseases, active acne, fungal infections, rashes, or skin cancer), you should take precautions and see your doctor before starting any microneedling treatments.

If you have a skin problem, it doesn't necessarily mean you won't be able to microneedle, but you should see your doctor beforehand to prevent provoking an inflammatory skin reaction that will aggravate any of the aforementioned conditions.

Keloid Scarring - If you've ever experienced keloid scarring (raised scarring), you should see a medical expert before undergoing microneedling.

Because microneedling increases the skin's trauma/healing response, if your skin's natural response is to develop a keloid scar, microneedling may cause an unwanted reaction.

Medications - If you're using drugs like accutane, antibiotics, antidepressants, medications that induce photosensitivity, or medications that cause high blood pressure, talk to your doctor before starting microneedling.

Some drugs will prevent you from microneedling, while others will allow you to do so with caution under your doctor's supervision. Before you begin microneedling, it's critical to double-check this appropriateness.

Cosmetic treatments - You must wait until your skin has fully recovered from cosmetic procedures such as chemical peels, laser, cosmetic surgery, filler injections, or cosmetic surgery before beginning microneedling. Before you begin microneedling, see your doctor to ensure that it will not interfere with the outcomes of any of your cosmetic procedures.