。
She has a pale face as if she were sick.
Literal
[topic-は] just-as sick is-[as-if-かのように] pale face [object-を] is-doing.
まるで~かのように is the most explicit simile/counterfactual frame — 'exactly as if X were the case.' The か preserves the sense that the comparison is hypothetical (literally 'as if [it were the case] that X'). 病気である ('be sick') is the formal copula version of 病気だ — であるかのように is the explicit hypothetical/literary version. 青い顔 literally 'blue face' is the standard Japanese phrase for 'pale face' — Japanese categorizes the pallor of fear or illness as 青 (blue/green) rather than the English 'white.' This 'blue for pale' mapping is a classic example of how color language differs across cultures.