For example, a person with signs of hyposalivation may not complain of xerostomia. Conversely a person who reports experiencing xerostomia may not show signs of reduced salivary secretions (subjective xerostomia). In the latter scenario, there are often other oral symptoms suggestive of oral dysesthesia ("burning mouth syndrome"). Some symptoms outside the mouth may occur together with xerostomia. These include:

Xerophthalmia (dry eyes). Inability to cry. Blurred vision. Photophobia (light intolerance). Dryness of other mucosae, e.g., nasal, laryngeal, and/or genital. Burning sensation. Itching or grittiness. Dysphonia (voice changes).There may also be other systemic signs and symptoms if there is an underlying cause such as Sjögrens syndrome, for example, joint pain due to associated rheumatoid arthritis. Cause
The differential of hyposalivation significantly overlaps with that of xerostomia. A reduction in saliva production to about 50% of the normal unstimulated level will usually result in the sensation of dry mouth. Altered saliva composition may also be responsible for xerostomia. Physiologic
Salivary flow rate is decreased during sleep, which may lead to a transient sensation of dry mouth upon waking. This disappears with eating or drinking or with oral hygiene. When associated with halitosis, this is sometimes termed "morning breath". Dry mouth is also a common sensation during periods of anxiety, probably owing to enhanced sympathetic drive. Dehydration is known to cause hyposalivation, the result of the body trying to conserve fluid. Physiologic age-related changes in salivary gland tissues may lead to a modest reduction in salivary output and partially explain the increased prevalence of xerostomia in older people.
It is associated with hyposalivation, as bacteria are able to enter the ductal system against the diminished flow of saliva. There may be swollen salivary glands even without acute infection, possibly caused by autoimmune involvement. Dysgeusia – altered taste sensation (e.g., a metallic taste) and dysosmia, altered sense of smell. Intraoral halitosis –  possibly due to increased activity of halitogenic biofilm on the posterior dorsal tongue (although dysgeusia may cause a complaint of nongenuine halitosis in the absence of hyposalivation). Burning mouth syndrome – a burning or tingling sensation in the mouth. Saliva that appears thick or ropey. Mucosa that appears dry. A lack of saliva pooling in the floor of the mouth during examination. Dysphagia – difficulty swallowing and chewing, especially when eating dry foods. Food may stick to the tissues during eating. The tongue may stick to the palate, causing a clicking noise during speech, or the lips may stick together. Gloves or a dental mirror may stick to the tissues. Fissured tongue with atrophy of the filiform papillae and a lobulated, erythematous appearance of the tongue. Saliva cannot be "milked" (expressed) from the parotid duct. Difficulty wearing dentures, e.g., when swallowing or speaking. There may be generalized mucosal soreness and ulceration of the areas covered by the denture. Mouth soreness and oral mucositis. Lipstick or food may stick to the teeth. A need to sip drinks frequently while talking or eating. Dry, sore, and cracked lips and angles of mouth. Thirst.However, sometimes the clinical findings do not correlate with the symptoms experienced.