Depigmentation is the lightening of the skin, or loss of pigment. Depigmentation of the skin can be caused by a number of local and systemic conditions. The pigment loss can be partial (injury to the skin) or complete (caused by vitiligo). It can be temporary (from tinea versicolor) or permanent (from albinism).

Most commonly, depigmentation of the skin is linked to people born with vitiligo, which produces differing areas of light and dark skin. These individuals, if they so decided to use a lightning process to even out their skin tone, could apply a topical cream containing the organic compound monobenzone to lessen the remaining pigment. The brand drug incorporating 20% monobenzone is Benoquin, made by ICN.

Increasingly, people who are not afflicted with the vitiligo experiment with lower concentrations of monobenzone creams in the hope of lightning their skin tone evenly. An alternate method of lightning is to use the chemical mequinol over an extended period of time. Both monobenzone and mequinol produce dramatic skin whitening, but react very differently. Mequinol leaves the skin looking extremely pale. However, tanning is still possible. It is important to notice that the skin will not go back to its original color after the none treatment of mequinol. Mequinol should not be used by people that are allergic to any ingredient in mequinol, if you are pregnant, if you have eczema, irritated or inflamed skin, an increased number of white blood cells or if you are sensitive to sunlight or must be outside for prolonged periods of time. Mequinol is used in Europe in concentrations ranging from 2-20% and is approved in many countries for the treatment of solar lentigines. Monobenzone applied topically completely removes pigment in the long term and vigorous sun-safety must to be adhered to for life to avoid severe sun burn and melanomas. People using monobenzone without previously having vitiligo do so because standard products containing hydroquinone or other lightning agents are not effective for their skin and due to price and active ingredient strength. However, monobenzone is not recommended for skin conditions other than vitiligo.

For stubborn pigmented lesions the Q-switched ruby laser, cryotherapy or TCA peels can be used to ensure the skin remains pigment-free.

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.

In mild cases, vitiligo patches can be hidden with makeup or other cosmetic camouflage solutions. If the affected person is pale-skinned, the patches can be made less visible by avoiding tanning of unaffected skin.

Liver spots (also known as age spot, solar lentigo, "lentigo senilis", "old age spot", "senile freckle") are es on the skin associated with aging and exposure to ultraviolet radiation from the sun. They range in color from light brown to red or black and are located in areas most often exposed to the sun, particularly the hands, face, shoulders, arms and forehead, and the scalp if bald.

The spots derive their name from the fact that they were once incorrectly believed to be caused by liver problems, but they are physiologically unrelated to the liver, save for a similar color. From the age of 40 onward the skin is less able to regenerate from sun exposure, and liver spots are very common in this age group, particularly in those who spend time in the sun.

In the overwhelming majority of cases, liver spots pose no threat and require no treatment, though they occasionally have been known to obscure the detection of skin cancer. However, despite being a benign condition, liver spots are sometimes considered unsightly and some people choose to have them removed. This can be done by electrosurgery, laser treatment, cryotherapy, or the use of depigmentation agents, such as hydroquinone, tretinoin, topical cysteamine, azelaic acid or alpha hydroxy acids.

Differently from the melanotic nevi and the verrucous nevi on the skin, age spots change with time in color and in shape. Misrepair-accumulation aging theory proposes a hypothesis on the development of age spots. Firstly, the development of a flat spot is a result of accumulation of aged basal cells. When the skin is aged, some aged cells that contain lipofuscin bodies cannot be removed. An aged cell will affect the functionality of the local tissue and promote the aging of its neighbor cells. By a feedback loop, more and more neighbor cells become aged and lipofuscin-containing. They aggregate and form a spot with an irregular shape. Secondly, protruding of a flat spot is a result of the death of aged cells in the spot and release of lipofuscin bodies. Isolation of the un-digestible lipofuscin bodies in a fibrotic capsule is essential for maintaining the structural integrity of the tissue. Successive encapsulation of dead cells and lipofuscin bodies results in the growth of a spot in three dimensions. The dense lipofuscin bodies in the capsule make a protruding spot soft and dark in color.

As halo nevi are only of cosmetic significance, no treatment is required, and patients will be asymptomatic. Although halo nevi are harmless, it is important to monitor the lesion on regular basis. Watch out for any changes in appearance of existing or new halo nevi. If there is any change in appearance or is associated with pain, itch, and infection, a doctor should be consulted immediately to exclude the possibility of melanoma.

Halo nevi are estimated to be present in approximately 1% of the general population, and are found to be more prevalent in people with vitiligo, malignant melanoma, or Turner syndrome. All races and sexes are equally susceptible to this disease, although a familial tendency has been reported. The average age of onset is in a person's teenage years.

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

Radiation burns are caused by exposure to high levels of radiation. Levels high enough to cause burn are generally lethal if received as a whole-body dose, whereas they may be treatable if received as a shallow or local dose.

Radiation burns should be covered by a clean, dry dressing as soon as possible to prevent infection. Wet dressings are not recommended. The presence of combined injury (exposure to radiation plus trauma or radiation burn) increases the likelihood of generalized sepsis. This requires administration of systemic antimicrobial therapy.

A lentigo () (plural lentigines, ) is a small pigmented spot on the skin with a clearly defined edge, surrounded by normal-appearing skin. It is a harmless (benign) hyperplasia of melanocytes which is linear in its spread. This means the hyperplasia of melanocytes is restricted to the cell layer directly above the basement membrane of the epidermis where melanocytes normally reside. This is in contrast to the "nests" of multi-layer melanocytes found in moles (melanocytic nevi). Because of this characteristic feature, the adjective "lentiginous" is used to describe other skin lesions that similarly proliferate linearly within the basal cell layer.

Lentigines are distinguished from freckles (ephelis) based on the proliferation of melanocytes. Freckles have a relatively normal number of melanocytes but an increased "amount" of melanin. A lentigo has an increased "number" of melanocytes. Freckles will increase in number and darkness with sunlight exposure, whereas lentigines will stay stable in their color regardless of sunlight exposure.

Lentigines by themselves are benign, however one might desire the removal or treatment of some of them for cosmetic purposes. In this case they can be removed surgically, or lightened with the use of topical depigmentation agents. Some common depigmentation agents such as azelaic acid and kojic acid seem to be inefficient in this case, however other agents might work well (4% hydroquinone, 5% topical cysteamine, 10% topical ascorbic acid).

Conditions characterized by lentigines include:

- Lentigo simplex

- Solar lentigo (Liver spots)

- PUVA lentigines

- Ink spot lentigo

- LEOPARD syndrome

- Mucosal lentigines

- Multiple lentigines syndrome

- Moynahan syndrome

- Generalized lentiginosis

- Centrofacial lentiginosis

- Carney complex

- Inherited patterned lentiginosis in black persons

- Partial unilateral lentiginosis

- Peutz-Jeghers syndrome

- Lentigo maligna

- Lentigo maligna melanoma

- Acral lentiginous melanoma

This disorder was first reported by Bruno Bloch, a Swiss dermatologist in 1926 and Marion Sulzberger, an American dermatologist in 1928.

There is no cure for HPV. Existing treatments are focused on the removal of visible warts, but these may also regress on their own without any therapy. There is no evidence to suggest that removing visible warts reduces transmission of the underlying HPV infection. As many as 80% of people with HPV will clear the infection within 18 months.

A healthcare practitioner may offer one of several ways to treat warts, depending on their number, sizes, locations, or other factors. All treatments can potentially cause depigmentation, itching, pain, or scarring.

Treatments can be classified as either physically ablative, or topical agents. Physically ablative therapies are considered more effective at initial wart removal, but like all therapies have significant recurrence rates.

Many therapies, including folk remedies, have been suggested for treating genital warts, some of which have little evidence to suggest they are effective or safe. Those listed here are ones mentioned in national or international practice guidelines as having some basis in evidence for their use.

Gardasil (sold by Merck & Co.) is a vaccine that protects against human papillomavirus types 6, 11, 16 and 18. Types 6 and 11 cause genital warts, while 16 and 18 cause cervical cancer. The vaccine is preventive, not therapeutic, and must be given before exposure to the virus type to be effective, ideally before the beginning of sexual activity. The vaccine is approved by the US Food and Drug Administration for use in both males and females as early as 9 years of age.

In the UK, Gardasil replaced Cervarix in September 2012 for reasons unrelated to safety. Cervarix had been used routinely in young females from its introduction in 2008, but was only effective against the high-risk HPV types 16 and 18, neither of which typically causes warts.

Lymphoma is the most common type of blood-related cancer in horses and while it can affect horses of all ages, it typically occurs in horses aged 4–11 years.

The disease can be treated with penicillin, tetracycline (not to be used in pregnant women), azithromycin or chloramphenicol, and can be prevented through contact tracing by public health officials. A single intramuscular injection of long-acting penicillin is effective against endemic treponematoses including pinta, yaws, and bejel

Treatment of small melanomas is often not necessary, but large tumors can cause discomfort and are usually surgically removed. Cisplatin and cryotherapy can be used to treat small tumors less than 3 centimeters, but tumors may reoccur. Cimetidine, a histamine stimulator, can cause tumors to regress in some horses, but may take up to 3 months to produce results and multiple treatments may be needed throughout the horse's life. There are few viable treatment options for horses with metastatic melanoma. However, gene therapy injections utilizing interleukin-12 and 18-encoding DNA plasmids have shown promise in slowing the progression of tumors in patients with metastatic melanoma.

Cessation of the drug at the first sign of toxicity is recommended. No treatment exists as yet for this disorder, so it is imperative that patients and their ophthalmologists be aware of the best practices for minimizing toxic damage.

Pinta (also known as Azul, Carate, Empeines, Lota, Mal del Pinto and Tina) is a human skin disease endemic to Mexico, Central America, and South America caused by infection with a spirochete, "Treponema pallidum carateum", which is morphologically and serologically indistinguishable from the bacterium that causes syphilis.

Associated visual loss rarely recovers and may even progress after the drug is discontinued.

Visual prognosis is generally good with prompt diagnosis and aggressive immunomodulatory treatment. Inner ear symptoms usually respond to corticosteroid therapy within weeks to months; hearing usually recovers completely. Chronic eye effects such as cataracts, glaucoma, and optic atrophy can occur. Skin changes usually persist despite therapy.

If the Hirschsprung's disease is treated in time, ABCD sufferers live otherwise healthy lives. If it is not found soon enough, death often occurs in infancy. For those suffering hearing loss, it is generally regressive and the damage to hearing increases over time. Digestive problems from the colostomy and reattachment may exist, but most cases can be treated with laxatives. The only other debilitating symptom is hearing loss, which is usually degenerative and can only be treated with surgery or hearing aids.

Treatment for the disease itself is nonexistent, but there are options for most of the symptoms. For example, one suffering from hearing loss would be given hearing aids, and those with Hirschsprung’s disorder can be treated with a colostomy.

The acute uveitis phase of VKH is usually responsive to high-dose oral corticosteroids; parenteral administration is usually not required. However, ocular complications may require an subtenon or intravitreous injection of corticosteroids or bevacizumab. In refractory situations, other immunosuppressives such as cyclosporine, or tacrolimus, antimetabolites (azathioprine, mycophenolate mofetil or methotrexate), or biological agents such as intravenous immunoglobulins (IVIG) or infliximab may be needed.

A vaccine that is similar to the effective canine melanoma vaccine has been created for equine melanoma and is being studied at the College of Veterinary Medicine at the University of Florida