The diagnosis of IP is established by clinical findings and occasionally by corroborative skin biopsy. Molecular genetic testing of the NEMO IKBKG gene (chromosomal locus Xq28) reveals disease-causing mutations in about 80% of probands. Such testing is available clinically.

In addition, females with IP have skewed X-chromosome inactivation; testing for this can be used to support the diagnosis.

Many people in the past were misdiagnosed with a second type of IP, formerly known as IP1. This has now been given its own name - 'Hypomelanosis of Ito' (incontinentia pigmenti achromians). This has a slightly different presentation: swirls or streaks of hypopigmentation and depigmentation. It is "not" inherited and does not involve skin stages 1 or 2. Some 33–50% of patients have multisystem involvement — eye, skeletal, and neurological abnormalities. Its chromosomal locus is at Xp11, rather than Xq28.

As Becker's nevus is considered a benign lesion, treatment is generally not necessary except for cosmetic purposes. Shaving or trimming can be effective in removing unwanted hair, while electrology or laser hair removal may offer a longer-lasting solution. Different types of laser treatments may also be effective in elimination or reduction of hyperpigmentation, though the results of laser treatments for both hair and pigment reduction appear to be highly variable.

A 1991 report documented the cases of nine patients with both Becker's nevus and malignant melanoma. Of the nine melanomas, five were in the same body area as the Becker's nevus, with only one occurring within the nevus itself. As this was apparently the first documented co-occurrence of the two diseases, there is so far no evidence of higher malignancy rates in Becker's nevi versus normal skin. Nonetheless, as with any abnormal skin growth, the nevus should be monitored regularly and any sudden changes in appearance brought to the attention of one's doctor.

Schamberg's disease can only be properly diagnosed by a healthcare provider. While reviewing medical history is important to diagnose this condition, it is essential that the purpuric lesions are physically examined. A skin biopsy will be taken to determine capillaritis of dermal vessels. Capillaritis or pigmented purpura is skin condition that has brown-reddish patches on the skin, which is caused by leaky capillaries. The skin biopsy is sent to a laboratory for a pathological examination, where the biopsy is observed under a microscope. In addition to the skin biopsy, dermatologists will perform a dermatoscopy. With the results from the biopsy and from the dermatoscopy, a doctor will be able to identify that the skin lesions are in fact due Schamberg's disease. To ensure that the skin lesions are not caused by other skin conditions or infections, doctors will order a complete blood count (CBC) and other blood tests. Blood tests are usually normal and they are only performed to rule out other bleeding disorders that cause purpura. Since Schamberg's disease is usually asymptomatic, there is not a lot of other tests that can be performed. This condition is easy to diagnose because the appearance of skin lesions on the skin is the first indicator that the lesions are due to Schamberg's disease.

Diagnosis is made primarily through physical assessment of the skin, family history of Mongolian spots, and subjective data given by the care giver. No tests are currently available for diagnosing Mongolian spots.

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

Schamberg's disease is caused by leaky blood vessels near the surface of the skin, capillaries, which allow red blood cells to slip through into the skin. The red blood cells in the skin then fall apart and release their iron, which is released from hemoglobin. The iron causes a rust color and this accounts for the orange tint of the rash that can be seen on the skin. The underlying cause of the leaky blood vessels is not known, but researchers are suggesting that there could be some potential triggers. Some possible triggers include viral infection, a hypersensitivity to some agent, and interaction of some medications, such as thiamine and aspirin. Even though there is no correlation with genetics, there have been a few cases where few people in a family had this condition.

Although the cause of capillary inflammation is unknown, certain preventive measures can be taken. Doctors may prescribe medications that enhance the circulation of blood, which can keep blood vessels strong and healthy. Daily intake of vitamin C has proven to be a natural home remedy that can prevent the onsite of any disease or infection. Doctors always recommend that their patients monitor what they eat because their diet could be a possible factor that contributes to this condition. A healthy body that receives nutritious meals is more likely to have a healthy life that does not revolve around a lot of health problems.

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

In cases of extensive vitiligo the option to de-pigment the unaffected skin with topical drugs like monobenzone, mequinol, or hydroquinone may be considered to render the skin an even colour. The removal of all the skin pigment with monobenzone is permanent and vigorous. Sun-safety must be adhered to for life to avoid severe sunburn and melanomas. Depigmentation takes about a year to complete.

An ultraviolet light can be used in the early phase of this disease for identification and to determine the effectiveness of treatment. Skin with vitiligo, when exposed to a blacklight, will glow blue. In contrast, healthy skin will have no reaction.

There does not yet exist a specific treatment for IP. Treatment can only address the individual symptoms.

Treatment is predominantly preventive. Avoidance of topical phenols and diets low in tyrosine may help. Replacement and repair of damaged tissue is also possible.

Hydroquinone-induced exogenous ochronosis is an avoidable dermatosis that is exceedingly difficult to treat.

However, some studies show that treatment may be possible with a Q-switched alexandrite (755 nm) laser.

It is recommended that individuals with this disorder stop using hydroquinone-containing compounds. It is important to be aware of this as dermatologists may think the symptoms a patient is exhibiting are a melasma, and prescribe a hydroquinone-containing cream.

Haber syndrome is a cutaneous disorder of hyperpigmentation characterized by reticulated pigmentation of the person's skin. A rare genodermatosis, its key features include "rosacea-like facial eruption[,] reticulated hyperpigmentation of major flexures, comedones on the back and neck, and pitted facial scars."

A study in Sweden showed that 21.5% of smokers and 3% of nonsmokers (genetic pigmentation or unknown cause) had lesions that could be classified as an oral melanin pigmentation. A gingival melanin index in 4 degrees was established. Already with a consumption of 1-3 cigarettes a day 9.3% of all 20.333 examined showed a smoker's melanosis. Pipe smokers had smoker's melanosis in 16.8%. One year after the start of cigarette smoking a clinically visible smoker's melanosis could be seen in 12.3% of women, and 17% among men.

In cigarette smokers who quit smoking, the number of individuals with smoker's melanosis becomes slowly less frequent after 2–3 months, but can still be seen in a few former smokers three years after smoking stop.

Although clinically visible genetic melanin pigmentations in the mouth are present in several ethnic groups all over the world, more mucosal areas will be melanin-pigmentet if tobacco products are used. Smoker's melanosis is found in India, Italy, Japan, Nigeria, Sweden, Turkey, USA, and several other countries.

Smoker's melanosis is expected to be found also in other tissue surfaces exposed to tobacco and tobacco smoke, for instance lips and in skin of the fingers holding the cigarette. Future studies will also show if the use of tobacco exaggerates the pigmentation of skin.

Discontinuing contact with the heat source is the initial treatment of erythema ab igne. If the area is only mildly affected with slight redness, the condition may resolve itself in a few months. If the condition is severe and the skin pigmented and atrophic, resolution is unlikely. In this case, there is a possibility that a squamous cell carcinoma or a neuroendocrine carcinoma such as a Merkel cell carcinoma may form. If there is a persistent sore that does not heal or a growing lump within the rash, a skin biopsy should be performed to rule out the possibility of skin cancer. If the erythema ab igne lesions demonstrate pre-cancerous changes, the use of 5-fluorouracil cream has been recommended. Abnormally pigmented skin may persist for years. Treatment with topical tretinoin or laser may improve the appearance.

Mongolian spots usually resolve by early childhood and hence no treatment is generally needed if they are located in the sacral area. However, sometimes it may be required for extra sacral lesions to have surgical correction. Q-switched alexandrite lasers have been used for treatment. Good results are obtained if treatment is initiated before the age of 20 years. In a study done by the University of Tokyo, the effectiveness of the Q-switched alexandrite laser in treating Mongolian spots was evaluated. A retrospective study was done from April 2003 to September 2011. 16 patients, aged 14-55, were treated with Q-switched alexandrite laser. A good therapeutic outcome was achieved on the whole group, however two patients with sacral Mongolian spots suffered from inflammatory hyperpigmentation, and two patients got post inflammatory hypopigmentation after seven sessions of laser treatment.

Pigmentation disorders are disturbances of human skin color, either loss or reduction, which may be related to loss of melanocytes or the inability of melanocytes to produce melanin or transport melanosomes correctly.

PVA usually has an underlying cause, attributed to existing skin diseases and disorders associated with a cutaneous lymphoma or inflammation. Mycosis fungoides is the common lymphoma believed to cause PVA, although it may be considered a precursor when the lymphoma is (hidden) and undiagnosed. Large plaque parapsoriasis is another common causes of PVA. Less common causes include autoimmune-related connective tissue diseases such as lupus, dermatomyositis and scleroderma. Dermatoses and those that are genetically inspired, called genodermatoses, may also be an underlying cause of PVA. Among them, xeroderma pigmentosum and Rothmund-Thomson syndrome (poikiloderma congenita) are thought to be the most prominent. Ingestion of substances containing arsenic, such as arsphenamine, has also been suggested as a least common cause. PVA can also be idiopathic (of unknown cause), as seen in a small number of cases.

Lesions usually disappear between 3 months to 3 years for those who stop smoking. Smoker's melanosis is a benign, normal physiological reaction, and does not develop into cancer. If it does not disappear, however, a biopsy can verify the diagnosis. If Smoker's melanosis is destroyed by excessive smoking, as in the hard palate of reverse smokers, who smoke with the glowing part of the cigarette inside the mouth for different reasons, a pale depigmented surface is first seen, indicating the loss of the protecting melanin. Then a red inflammation sometimes occurs and cancer development may follow. In reverse smokers it is important to inspect regularly the areas with smoker's melanosis to detect any melanin destruction, in order to stop smoking in time and thus prevent a cancer to develop.

Phytophotodermatitis can be prevented by staying indoors after handling the above substances. However, the primary triggering mechanism is UV-A radiation (320–380 nm) which windows are not guaranteed to filter out.

Many different topical and oral medications can be used to treat the inflammatory reaction of phytophotodermatitis. A dermatologist may also prescribe a bleaching cream to help treat the hyperpigmentation and return the skin pigmentation back to normal. If they do not receive treatment, the affected sites may develop permanent hyperpigmentation or hypopigmentation.

Excision biopsy is required to confirm the diagnosis of saree cancer. In many cases local excision with skin grafting is considered the appropriate treatment.

Different ways of wearing the petticoat may help saree-wearers to prevent saree cancer. Some such strategies are:

- Loosening the petticoat

- Changing the usual rope-like belt to broader ones that reduce pressure on the area

- Continuously changing the level at which the petticoat is tied

"Ephelides" describes a freckle which is flat and light brown or red and fades with reduction of sun exposure. Ephelides are more common in those with light complexions, although they are found on people with a variety of skin tones. The regular use of sunblock can inhibit their development.

Liver spots (also known as sun spots and lentigines) look like large freckles, but they form after years of exposure to the sun. Liver spots are more common in older people.

DC is associated with shorter life expectancy, but many live to at least age 60.

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.