Option 1: Itailtai - There is no known disease called Itailtai caused by Nickel. This option is incorrect.

Option 2: Dermatitis - Nickel is a common cause of allergic contact dermatitis. When the skin comes into contact with nickel, it can cause a red, itchy rash. This is a well-known condition and is the correct answer.

Option 3: Learning disability - Nickel exposure is not known to cause learning disabilities. This option is incorrect.

Option 4: Asthma - Nickel exposure is not a common cause of asthma. Although nickel can trigger asthma symptoms in some individuals, it is not generally considered the primary cause of the condition. Therefore, this option is incorrect.

In conclusion, the correct answer is option 2, Dermatitis, as nickel is known to cause allergic contact dermatitis.