Postnasal drip or upper airway cough syndrome: This is often the most common cause of a dry cough, especially when accompanied by a hoarse voice, due to the irritation of the vocal cords by the dripping mucus.
Acid reflux (Gastroesophageal reflux disease, GERD): GERD can cause stomach acid to flow up into the throat, leading to irritation and a dry cough, along with hoarseness due to the acid affecting the vocal cords.

Viral pharyngitis or laryngitis: Viral infections can cause inflammation of the throat or voice box, leading to a dry cough and hoarseness.
Allergic rhinitis: Allergies can lead to postnasal drip, which irritates the throat and vocal cords, causing cough and hoarseness.
Asthma: Though more commonly associated with a productive cough, asthma can sometimes present with a dry cough, especially if the asthma is mild or if the patient is not producing much mucus.

Laryngeal cancer: Though rare, especially in young individuals, laryngeal cancer can present with hoarseness and a persistent cough. Early detection is crucial for effective treatment.
Tuberculosis (TB): TB can cause a chronic cough and hoarseness, among other symptoms. It's essential to consider TB, especially if the patient has been exposed to someone with TB or has risk factors such as immunocompromisation.
Pneumonia: Certain types of pneumonia, especially those caused by atypical bacteria, can present with a dry cough and hoarseness.

Sarcoidosis: This autoimmune disease can affect various parts of the body, including the lungs and lymph nodes, and can cause a dry cough and hoarseness among other symptoms.
Relapsing polychondritis: A rare autoimmune disorder that can cause inflammation of the cartilage in the trachea and larynx, leading to symptoms like a dry cough and hoarseness.
Vocal cord lesions (e.g., polyps, nodules): These can cause hoarseness and, occasionally, a dry cough if they irritate the surrounding areas.