If a child has a severe impairment(s) that does not meet or medically equal any listing, the Social Security Administration (SSA) will then look to see if the child functionally equals the listings. To functionally equal the listing, the child’s impairments must result in marked limitations in two domains, or extreme limitation in one domain.
The fourth domain used by SSA is called 4. Health and Physical Well-Being. In this domain, SSA considers the physical effects of physical and mental impairments of the child. Unlike the other domains, this domain does not address typical development and functioning. This domain addresses how such things as recurrent illness, the side effects of medication, and the need for ongoing treatment affect a child’s body.
It is important to remember that the cumulative physical effects of a child’s physical or mental impairment(s) can vary in kind and intensity, and can affect each child in a different way. As with all other domains, SSA does not consider the limitations in this domain unless it results from a medically determinable impairment(s). However, it is very unlikely that a child who has a significant problem in this domain does not have an impairment that causes the problem.