Is Nussallergie der, die or das?

The correct German article for Nussallergie is die. The noun Nussallergie is Feminine. So you always say: die Nussallergie. Learn the article together with the noun — German nouns don't follow predictable gender rules most of the time.

The plural of Nussallergie is: die Nussallergien. In the plural, every German noun takes the article "die". So: die Nussallergien. Example: ein Nussallergie → zwei Nussallergien.

Correct: die Nussallergien. The form "die Nussallergies" is wrong. The plural of die Nussallergie is die Nussallergien. In the nominative plural, you always use the article "die".

die Nussallergie follows the four German cases. Nominative: die Nussallergie, Accusative: die Nussallergie, Dative: der Nussallergie, Genitive: der Nussallergie. In plural: die Nussallergien / den Nussallergien. Learn these forms together with the noun.

The genitive singular of die Nussallergie is: der Nussallergie. The genitive plural is der Nussallergien. German uses the genitive to express possession or belonging. Example: die Farbe der Nussallergie.

The dative plural of Nussallergie is: den Nussallergien. In German, dative plural nouns usually end in "-n". So you say: "mit den Nussallergien". Use this case after prepositions like mit, von, bei, zu.

Nussallergie ends in -e. German nouns with this ending are almost always feminine. Nouns ending in -e are often feminine (die), especially two-syllable words. That's why the article for Nussallergie is die.

Nussallergie is a noun and must be capitalized in German. You'll find example sentences above for each case. The article die stays the same in nominative singular but changes in other cases. Practice declension in your own sentences.

Yes, Nussallergie is a noun (also called a substantive). German nouns are always capitalized. The article for Nussallergie is die. Every German noun has a fixed article you must memorize.