Blepharitis: This is a common condition, especially in adolescents, characterized by inflammation of the eyelid margin, often caused by bacterial or demodex mites. The symptoms of redness, swelling, and pain, especially upon waking, align with blepharitis.

Hordeolum (Stye): A localized infection or inflammation of the eyelid margin involving hair follicles of the eyelashes or meibomian glands. It presents with a painful, swollen nodule on the eyelid.
Chalazion: A small bump on the eyelid due to a blocked oil gland. While often painless, a large chalazion can cause discomfort and swelling.
Allergic Conjunctivitis: Seasonal or environmental allergies can cause eyelid swelling, redness, and itching, often accompanied by conjunctival injection.

Orbital Cellulitis: A serious infection of the tissues surrounding the eye, which can cause eyelid swelling, pain, and fever. It requires prompt antibiotic treatment to prevent serious complications.
Preseptal Cellulitis: An infection of the eyelid and skin anterior to the orbital septum, which can mimic orbital cellulitis but is less severe. However, it can progress to orbital cellulitis if not treated.
Angioedema: A condition characterized by rapid swelling of the dermis, subcutaneous tissue, mucosa, and submucosal tissues. It can be life-threatening if it involves the airway.

Thyroid-Associated Orbitopathy: Although more common in adults, this condition can occur in adolescents and is associated with thyroid disease. It can cause eyelid swelling, among other symptoms.
Sarcoidosis: A systemic disease that can affect any organ, including the eyes, causing uveitis, conjunctivitis, and eyelid swelling.
Wegener's Granulomatosis (Granulomatosis with Polyangiitis): A rare autoimmune disorder that can affect various parts of the body, including the eyes, causing inflammation and damage.