Rosacea: A common condition in older adults, characterized by redness, flushing, and visible blood vessels on the face, which can sometimes extend to the chest. The age and symptoms align with this diagnosis.

Sun Damage/Photodamage: Prolonged sun exposure can lead to redness and discoloration on sun-exposed areas like the face and chest, especially in older adults.
Eczema/Dermatitis: Various forms of dermatitis can cause redness and may affect the face and chest. Atopic dermatitis, contact dermatitis, and seborrheic dermatitis are possibilities.
Hormonal Fluctuations: Changes in hormone levels, particularly during menopause, can lead to flushing and redness, often affecting the face and chest.

Lupus: Systemic lupus erythematosus (SLE) can cause a butterfly-shaped rash on the face and may also affect the chest. Although less common, missing this diagnosis could be serious due to its systemic implications.
Carcinoid Syndrome: This rare condition can cause flushing and redness, typically affecting the face and upper body, including the chest. It's associated with carcinoid tumors and has significant health implications if not addressed.
Thyroid Disorders: Both hyperthyroidism and hypothyroidism can cause skin changes, including redness and flushing, particularly on the face and chest.

Sarcoidosis: A condition that can cause skin lesions and redness, among other systemic symptoms. It's less common but should be considered in the differential diagnosis due to its potential for serious complications.
Polycythemia Vera: A myeloproliferative disorder that can lead to increased red blood cell mass, causing flushing and redness, particularly in the face and upper body.
Mastocytosis: A condition characterized by the accumulation of mast cells in the skin, which can cause flushing, redness, and other skin symptoms, particularly in response to triggers.