Cysts develop within the deeper skin tissue as a result of an ingrown hair follicle. They become filled with a fluid and are often large enough to cause some skin sensitivity. They are usually harmless, but can be considered unattractive by those who have them, in which case they can be drained through cyst aspiration or excised with minor surgery. Although cysts are generally benign growths, it’s still advisable to have them examined by a physician who can recommend the best method of treatment. There are many different types of cysts that appear on the body, and they grow most commonly on the scalp, face and fingernails.