Lesions which greatly deviate from the common characteristics are labeled as an "ugly duckling", and further professional exam is required. The "little red riding hood sign", suggests that individuals with fair skin and light colored hair might have difficult-to-diagnose melanomas. Extra care and caution should be rendered when examining such individuals as they might have multiple melanomas and severely dysplastic nevi. A dermatoscope must be used to detect "ugly ducklings", as many melanomas in these individuals resemble non-melanomas or are considered to be "wolves in sheep clothing". These fair skinned individuals often have lightly pigmented or amelanotic melanomas which will not present easy-to-observe color changes and variation in colors. The borders of these amelanotic melanomas are often indistinct, making visual identification without a dermatoscope very difficult. People with a personal or family history of skin cancer or of dysplastic nevus syndrome (multiple atypical moles) should see a dermatologist at least once a year to be sure they are not developing melanoma. Management
First, a diagnosis must be made. If the lesion is a seborrheic keratosis, then shave excision, electrodesiccation or cryosurgery may be performed, usually leaving very little if any scarring. If the lesion is suspected to be a skin cancer, a skin biopsy must be done first, before considering removal. This is unless an excisional biopsy is warranted. If the lesion is a melanocytic nevus, one has to decide if it is medically indicated or not.
Experimentally, local anaesthetic injections and tying of the arteries is reported to trigger the development of tissue changes similar to NS in lab rats. Factors which are thought to cause this ischemia are listed below, however sometimes there is no evident predisposing factor or initiating event. Trauma e.g. during intubation, or surgical procedures
Local anesthetic injection
Smoking
Alcohol
Diabetes mellitus
Vascular disease, (e.g. arteriosclerosis)
Pressure from a dental prosthesis
Allergy
Bulimia
Infection
Ionizing radiation

Diagnosis
Differentiation between this and SCC would be based on a history of recent trauma or dental treatment in the area. Immunohistochemistry may aid the diagnosis. If the lesion is NS, there will be focal to absent immunoreactivity for p53, low immunoreactivity for MIB1 (Ki-67), and the presence of 4A4/p63- and calponin-positive myoepithelial cells. Treatment
No surgery is required. Prognosis
Healing is prolonged, and usually takes 6–10 weeks. The ulcer heals by secondary intention. Epidemiology
The condition is rare. The typical age range of those affected by the condition is about 23–66 years of age. It usually occurs in smokers. The male to female ratio has been reported as 1.95:1, and 2.31:1. History
NS was first reported by Abrams et al. in 1973. Notes
References


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