Detailed answer

Hair and scalp epidermoid cysts are typically caused by the blockage of hair follicles or the entrapment of skin cells beneath the skin surface. They are not directly linked to allergies to skincare products. Allergies to skincare products usually manifest as irritation, redness, itching, or rashes on the skin. If you suspect you have a hair or scalp cyst, it is advisable to consult a dermatologist who can properly diagnose and treat the condition.