The management of a nevus depends on the specific diagnosis, however, the options for treatment generally include the following modalities:

Nevi are typically diagnosed clinically with the naked eye or using dermatoscopy. More advanced imaging tests are available for distinguishing melanocytic nevi from melanoma, including computerized dermoscopy and image analysis. The management of nevi depends on the type of nevus and the degree of diagnostic uncertainty. Some nevi are known to be benign, and may simply be monitored over time. Others may warrant more thorough examination and biopsy for histopathological examination (looking at a sample of skin under a microscope to detect unique cellular features). For example, a clinician may want to determine whether a pigmented nevus is a type of melanocytic nevus, dysplastic nevus, or melanoma as some of these skin lesions pose a risk for malignancy. The ABCDE criteria (asymmetry, border irregularity, color variegation, diameter > 6 mm, and evolution) are often used to distinguish nevi from melanomas in adults, while modified criteria (amelanosis, bleeding or bumps, uniform color, small diameter or de novo, and evolution) can be used when evaluating suspicious lesions in children. In addition to histopathological examination, some lesions may also warrant additional tests to aid in diagnosis, including special stains, immunohistochemistry, and electron microscopy. Typically; the nevi which exist since childhood are harmless

Clinical diagnosis can be made with the naked eye using the ABCD guideline or by using dermatoscopy. An online-screening test is also available to help screen out benign moles.

A doctor will take a thorough medical history, and may take blood tests as well as examining liver and kidney function. Improvements have also been reported from treating malnutrition associated with zinc deficiency and other minerals. Intracellular (red blood cell) assays are more sensitive than tests for plasma levels.

Treatment of manifestations: special hair care products to help manage dry and sparse hair; wigs; artificial nails; emollients to relieve palmoplantar hyperkeratosis.

It often requires a dermatologist to fully evaluate moles. For instance, a small blue or bluish-black spot, often called a blue nevus, is usually benign but often mistaken for melanoma. Conversely, a junctional nevus, which develops at the junction of the dermis and epidermis, is potentially cancerous.

A basic reference chart used for consumers to spot suspicious moles is found in the mnemonic A-B-C-D, used by institutions such as the American Academy of Dermatology and the National Cancer Institute. The letters stand for asymmetry, border, color, and diameter. Sometimes, the letter E (for elevation or evolving) is added. According to the American Academy of Dermatology, if a mole starts changing in size, color, shape or, especially, if the border of a mole develops ragged edges or becomes larger than a pencil eraser, it would be an appropriate time to consult with a physician. Other warning signs include a mole, even if smaller than a pencil eraser, that is different from the others and begins to crust over, bleed, itch, or become inflamed. The changes may indicate developing melanomas. The matter can become clinically complicated because mole removal depends on which types of cancer, if any, come into suspicion.

A recent and novel method of melanoma detection is the "ugly duckling sign" It is simple, easy to teach, and highly effective in detecting melanoma. Simply, correlation of common characteristics of a person's skin lesion is made. 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.

HED2 is suspected after infancy on the basis of physical features in most affected individuals. GJB6 is the only gene known to be associated with HED2. Targeted mutation analysis for the four most common GJB6 mutations is available on a clinical basis and detects mutations in approximately 100% of affected individuals. Sequence analysis is also available on a clinical basis for those in whom none of the four known mutations is identified.

Surgical excision is common and is a very effective mode of treatment.

Some tests which detect cancer could be called "screening for epithelial dysplasia". The principle behind these tests is that physicians expect dysplasia to occur at the same rate in a typical individual as it would in many other people. Because of this, researchers design screening recommendations which assume that if a physician can find no dysplasia at certain time, then doing testing before waiting until new dysplasia could potentially develop would be a waste of medical resources for the patient and the healthcare provider because the chances of detecting anything is extremely low.

Some examples of this in practice are that if a patient whose endoscopy did not detect dysplasia on biopsy during screening for Barrett's esophagus, then research shows that there is little chance of any test detecting dysplasia for that patient within three years.

Individuals at average-risk for colorectal cancer should have another screening after ten years if they get a normal result and after five years if they have only one or two adenomatous polyps removed.

Treatment is by excisional biopsy, wide local excision and possibly sentinel node biopsy. Spread of disease to local lymph nodes or distant sites (typically brain, bone, skin and lung) marks a decidedly poor prognosis.

In approximately half of suspected nail fungus cases there is actually no fungal infection, but only some nail dystrophy. Before beginning oral antifungal therapy the health care provider should confirm a fungal infection. Administration of treatment to persons without an infection is unnecessary health care and causes needless exposure to side effects.

Most instances of onycholysis without a clear cause will heal spontaneously within a few weeks. The most commonly recommended treatment is to keep the nail dry as much as possible and allow the nail to slowly reattach. Trimming away as much loose nail as can be done comfortably will prevent the nail from being pried upwards. Cleaning under the nail is not recommended as this only serves to separate the nail further. Bandages are also to be avoided. When kept dry and away from further trauma, the nail will reattach from the base upward (i.e., from proximal to distal).

If the underlying cause of the condition is not found and the nail continues to detach despite conservative treatment, the nail bed may begin to form a granular layer of abnormal cells on its surface. After six months of detachment, this layer is likely to prevent the adhesion of any new nail tissue, possibly leading to permanent deformity.

Onychomatricoma is a cutaneous condition characterized by a distinctive tumor of the nail matrix.

This nail disease can mimic many nail problems and should be examined and biopsied by a dermatologist. In particular, a main concern is the malignant and destructive potential that may exist.

Also known as "scoop", "scallop", or "shave" excisional biopsy, or "shave excision". A trend has occurred in dermatology over the last 10 years with the advocacy of a deep shave excision of a pigmented lesion An author published the result of this method and advocated it as better than standard excision and less time consuming. The added economic benefit is that many surgeons bill the procedure as an excision, rather than a shave biopsy. This save the added time for hemostasis, instruments, and suture cost. The great disadvantage, seen years later is the numerous scallop scars, and a very difficult to deal with lesions called a "recurrent melanocytic nevus". What has happened is that many "shave" excisions does not adequately penetrate the dermis or subcutanous fat enough to include the entire melanocytic lesion. Residual melanocytes regrow into the scar. The combination of scarring, inflammation, blood vessels, and atypical pigmented streaks seen in these recurrent nevus gives the perfect dermatoscopic picture of a melanoma. When a second physicians re-examine the patient, he or she has no choice but to recommend the reexcision of the scar. If one does not have access to the original pathology report, it is impossible to tell a recurring nevus from a severely dysplastic nevus or a melanoma. As the procedure is widely practiced, it is not unusual to see a patient with dozens of scallop scars, with as many as 20% of the scars showing residual pigmentation. The second issue with the shave excision is fat herniation, iatrogenic anetoderma, and hypertrophic scarring. As the deep shave excision either completely remove the full thickness of the dermis or greatly diminishing the dermal thickness, subcutanous fat can herniate outward or pucker the skin out in an unattractive way. In areas prone to friction, this can result in pain, itching, or hypertrophic scarring.

Melanonychia is a black or brown pigmentation of the normal nail plate, and may be present as a normal finding on many digits in African-Americans, as a result of trauma, systemic disease, or medications, or as a postinflammatory event from such localized events as lichen planus or fixed drug eruption.

There are two types, longitudinal and transverse melanonychia. Longitudinal melanonychia may be a sign of subungual melanoma (acral lentiginous melanoma), although there are other diagnoses such as chronic paronychia, onychomycosis, subungual hematoma, pyogenic granuloma, glomus tumour, subungual verruca, mucous cyst, subungual fibroma, keratoacanthoma, carcinoma of the nail bed, and subungual exostosis.

The treatment of an ingrown toenail partly depends on its severity.

Nail inspection can give hints to the internal condition of the body as well.

Nail disease can be very subtle and should be evaluated by a dermatologist with a focus in this particular area of medicine. A nail technician may be the first to note a subtle change in nail health.

Usual diagnosis is via radiograph, patient history, biopsy is rarely needed. Periodic follow ups should included additional radiographs that show minimal growth or regression.

Some recommend avulsion of the nail plate with surgical destruction of the nail matrix with phenol or the carbon dioxide laser, if the blood supply is good.

Dysplastic nails are a cutaneous condition, and may be a subtle finding of ridging, flaking, or poor growth of the nails, or more diffuse with nearly complete loss of nails. This condition may be seen in a number of syndromes, including Dyskeratosis congenita and Nail–patella syndrome.

Mild to moderate cases are often treated conservatively with warm water and epsom salt soaks, antibacterial ointment and the use of dental floss. If conservative treatment of a minor ingrown toenail does not succeed, or if the ingrown toenail is severe, surgical treatment may be required. A "gutter splint" may be improvised by slicing a cotton-tipped wooden applicator diagonally to form a bevel and using this to insert a wisp of cotton from the applicator head under the nail to lift it from the underlying skin after a foot soak.

Longitudinal leukonychia is far less common and features smaller 1mm white longitudinal lines visible under the nail plate. It may be associated with Darier's disease.

Screening for melanoma in FAMMM kindreds should begin at age 10 with a baseline total body skin examination including scalp, eyes, oral mucosa, genital area, and nail, as family members may develop melanoma in their early teens.

At Mayo Clinic, FAMMM patients with a confirmed mutation and family history of pancreatic cancer are offered screening with either high-resolution pancreatic protocol CT, MRI, or endoscopic ultrasound starting at age 50 or 10 years younger than the earliest family member with pancreas cancer. They are counseled on the lack of evidence-based data to support screening, and on the limitations of our current technology to detect a lesion at a stage amenable to therapy.

Even though the ideal method of diagnosis of melanoma should be complete excisional biopsy, the location of the melanoma may require alternatives. Dermatoscopy of acral pigmented lesions is very difficult but can be accomplished with diligent attention. Initial confirmation of the suspicion can be done with a small wedge biopsy or small punch biopsy. Thin deep wedge biopsies can heal very well on acral skin, and small punch biopsies can give enough clue to the malignant nature of the lesion. Once this confirmatory biopsy is done, a second complete excisional skin biopsy can be performed with a narrow surgical margin (1 mm). This second biopsy will determine the depth and invasiveness of the melanoma, and will help to define what the final treatment will be. If the melanoma involves the nail fold and the nail bed, complete excision of the nail unit might be required. Final treatment might require wider excision (margins of 0.5 cm or more), digital amputation, lymphangiogram with lymph node dissection, or chemotherapy.

Pure hair-nail type ectodermal dysplasia is a genetic mutation in the "hair matrix and cuticle keratin KRTHB5 gene" that causes ectodermal dysplasia of hair and nail type. Manifestations of this disorder include onychodystrophy and severe hypotrichosis. It represents as an autosomal dominant trait.