Clinical course
The characteristic symptoms of dengue are sudden-onset fever, headache (typically located behind the eyes), muscle and joint pains, and a rash. An alternative name for dengue, "breakbone fever", comes from the associated muscle and joint pains. The course of infection is divided into three phases: febrile, critical, and recovery.The febrile phase involves high fever, potentially over 40 °C (104 °F), and is associated with generalized pain and a headache; this usually lasts two to seven days. Nausea and vomiting may also occur. A rash occurs in 50–80% of those with symptoms in the first or second day of symptoms as flushed skin, or later in the course of illness (days 4–7), as a measles-like rash. A rash described as "islands of white in a sea of red" has also been observed. Some petechiae (small red spots that do not disappear when the skin is pressed, which are caused by broken capillaries) can appear at this point, as may some mild bleeding from the mucous membranes of the mouth and nose. The fever itself is classically biphasic or saddleback in nature, breaking and then returning for one or two days.In some people, the disease proceeds to a critical phase as fever resolves. During this period, there is leakage of plasma from the blood vessels, typically lasting one to two days. This may result in fluid accumulation in the chest and abdominal cavity as well as depletion of fluid from the circulation and decreased blood supply to vital organs.
Corneal sensitivity test: performed by placing a cotton wad or cotton thread in contact with the corneal surface: this only allows to determine whether corneal sensitivity is normal, reduced or absent; or using an esthesiometer that allows to assess corneal sensitivity. Tear film function test, such as Schirmers test, and tear film break-up time. Fluorescein eye stain test, which shows any damage to the corneal and conjunctival epithelium

Classification
According to Mackies classification, neurotrophic keratitis can be divided into three stages based on severity:

Stage I: characterized by alterations of the corneal epithelium, which is dry and opaque, with superficial punctate keratopathy and corneal oedema. Long-lasting neurotrophic keratitis may also cause hyperplasia of the epithelium, stromal scarring and neovascularization of the cornea. Stage II: characterized by development of epithelial defects, often in the area near the centre of the cornea. Stage III: characterized by ulcers of the cornea accompanied by stromal oedema and/or melting that may result in corneal perforation. Treatment
Early diagnosis, targeted treatment according to the severity of the disease, and regular monitoring of patients with neurotrophic keratitis are critical to prevent damage progression and the occurrence of corneal ulcers, especially considering that the deterioration of the condition is often poorly symptomatic.The purpose of treatment is to prevent the progression of corneal damage and promote healing of the corneal epithelium. The treatment should always be personalized according to the severity of the disease.