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Male pattern baldness (go to androgenetic alopecia) | Mastocytosis | Measles | Melanomas | Melasma | Milaria | Moles | Morphoea (see scleroderma) | Molluscum contagiosum | Mongolian spot | Moniliasis (go to candidiasis) | Mucous cyst | Mycosis fungoides

MASTOCYTOSIS

Mastocytosis refers to abnormal collections of mast cells in the skin. Mast cells are large cells with granules containing chemicals such as heparin, serotonin and histamine. When mast cells degranulate, these chemicals (notably histamine) are released, causing urticaria (weals), redness and itching.

Mastocytosis is classified into the following varieties:
  • Cutaneous mastocytosis when only the skin is affected
     
    • Mastocytoma (usually solitary).
    • Urticaria pigmentosa (usually multiple).
    • Diffuse cutaneous mastocytosis.
    • Telangiectasia eruptiva macularis perstans.
     
  • Systemic mastocytosis when internal organs are involved.

    Cause

  • Unknown.

    Symptoms

  • Single or multiple brown or orange brown papules (bumps) or patches that itch, swell and sometimes blister when stroked.
  • May occur on the body, neck or arm, especially near the wrist.
  • Usually affects children at birth or within the first 1 year. It may occasionally affect adults, as well.
  • In some patients, the urticaria pigmentosa is more freckle-like and causes the skin to develop a darkened appearance with small telangiectasias (broken capillaries) on the surface. This form is known as telangiectasia eruptiva macularis perstans.
  • Diffuse cutaneous mastocytosis may cause a yellowish thickening of the skin or erythroderma.
  • The diagnostic sign of cutaneous mastocytosis is known as Darier's sign wherein the affected area swells, developes a weal or blisters when it is rubbed.
  • Systemic mastocytosis may cause enlargement of the liver, spleen and lymph glands or affect the bones and the gastrointestinal tract.
  • Childhood cases of cutaneous mastocytosis usually resolve on their own, usually by adolescence. Adult cases tend to be more persistent.

    Complications

  • Extensive urticaria pigmentosa may cause symptoms of histamine release such as flushing, nausea, vomiting, upper stomach pain and even shock. This usually occurs when the person takes drugs that cause the mast cells to degranulate.
  • Adults with urticaria pigmentosa or telangiectasia macularis eruptiva perstans may sometimes go on to develop systemic mastocytosis.
  • Some patients with systemic mastocytosis may go on to develop mast cell leukaemia where malignant mast cells can be found circulating in the blood.

    What you can do

  • You should consult the doctor.
  • Avoid drugs that cause mast cells to degranulate. Examples include alcohol and codeine. Other drugs to watch out for include dextran, polymyxin B, morphine, scopolamine and d-tubocurarine which may be used by doctors.

    What the doctor may do

  • Perform a skin biopsy to confirm the diagnosis.
  • Examine and investigate for other organ involvement.
  • Prescribe oral antihistamines, topical steroids or oral disodium cromoglycate (which is a mast cell stabiliser). PUVA and interferon may be used in adults with severe urticaria pigmentosa.
  • Follow-up closely.

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MEASLES

Measles is a childhood viral infection that affects the skin, eyes and the respiratory system.

    Cause

  • Measles virus which is transmitted through droplet infection. The incubation period is 10 - 14 days.

    Symptoms

  • Measles usually begins with high fever and cold symptoms such as runny nose, conjunctivitis (red eyes) and a dry hacking cough.
  • The rash appears 3 - 4 days later, along the hairline and around the ears and then spreads downwards to the face, trunk and limbs. The rash begins as numerous red spots which later join to form large red blotches. After about 3 days, the rash fades in the order it appears with bran-like shedding of skin scales.
  • Koplik's spots (white spots) on the inside of the cheeks opposite the premolar teeth are diagnostic of measles. These spots appear on the second or third day of the fever and disappear a few days after the rash appears.
  • There may be a generalised enlargement of the lymph glands. Photophobia or intolerance of bright lights is common.

    Complications

  • Otitis media (inflammation of the middle ear).
  • Pneumonia (lung inflammation).
  • Encephalitis (brain inflammation), causing headache, nausea, vomiting, epilepsy and coma.
  • Sclerosing panencephalitis, a rare progressive brain disorder may develop many years after the infection.
  • Death may very rarely result from complications such as pneumonia and encephalitis.
  • There is a 25% risk of feotal death when measles occurs in a pregnant women.

    What you can do

  • You should consult a doctor for confirmation and to exclude complications.
  • Rest, drink lots of fluid.
  • Take fever medicines (not aspirin as its use has been associated with the development of Reye's syndrome, a life-threatening condition causing brain and liver inflammation.
  • Take antihistamines and apply a soothing lotion such as calamine to relieve itching.
  • If a child has fever above 38.5oC, sponge to bring the temperature down and reduce the risk of febrile fits.
  • Use dim lighting if the eyes are irritated by bright lights.
  • Go to the hospital immediately if vomiting, epilepsy or breathing difficulties develop.

    Prevention

  • Measles can be prevented by vaccination. Most children are vaccinated at 1 - 3 years of age.

    What the doctor may do

  • Confirm the diagnosis.
  • Treat the complications.

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MELANOMAS, MALIGNANT MELANOMAS

Malignant melanomas or cancerous moles are the most feared skin cancers because of their potential to spread to other parts of the body. They are more common among fair-skinned individuals, especially those of Northern European or Celtic origin and may arise in pre-existing moles such as congenital and dysplastic naevi.

    Causes

  • A cancer arising from the melanocytes or pigment cells.
     
    Predisposing factors
  • Fair skin types I and II with a history of over-exposure to the sun.
  • A history of severe sunburns during childhood increases the risk of melanoma developing.
  • Inherited tendency. The risk of melanoma is increased if there is a family history of melanoma.
  • Dysplastic naevi (atypical moles). Non-familial or sporadic cases are associated with a slightly increased risk of developing malignant melanoma but familial dysplastic naevi with a family history of melanoma in two or more close relatives is associated with an almost 100% lifetime risk of developing a melanoma.
  • Large or giant congenital naevi are associated with a higher risk of developing malignant melanoma.

    Symptoms
    Malignant melanomas may arise on normal skin or in a pre-existing naevus such as congenital naevi and dysplastic naevi.

  • Melanomas are usually uneven in colour and and have a irregular outline. They may have any combination of brown, black, blue grey or black. Amelanotic melanomas are skin-coloured rather than pigmented.
  • Untreated, melanomas grow in size and thickness and become nodular. They may eventually ulcerate and bleed.
  • A particular type of melanoma known as acral lentiginous melanoma occurs on the extremities such as the palms, soles, fingers and toes. It is the most common type of melanoma in Asians and blacks. Sometimes, it may occur as a black streak in the nail.
  • Lentigo maligna is a type of early melanoma that occurs on the sun-exposed skin of the elderly.

    The American Academy of Dermatology's ABCD signs lists the danger signs to look out for in a mole. These signs are essentially, also those of a dysplastic naevus-

     
    • Asymmetry which means one side does not match the other.
    • Borders that are irregular.
    • Colour variation within the lesion such as various shades of red and blue mixed with areas of black, white or brown.
    • Diameter over 6mm.


    Other signs
    to watch out for include:

     
    • A mole that appears for the first time after the age of 35 years.
    • Bleeding, oozing, crusting or ulceration.
    • Pain, tenderness or itching.
    • Inflammation around the mole.
    • Nodule developing in the centre.

      Malignant melanoma.
    Click on image for larger view

    Complications

  • May spread to internal organs, causing death.

    What you can do

  • You should consult a doctor if you have a suspicious mole because early removal or melanomas can result in cure.
  • You should examine your skin regularly, especially if you have the predisposing factors mentioned above. It is a good idea to get your spouse or a close relative to check your back regularly, as well.
  • Melanomas can be prevented by protecting the skin against the sun (see sun protection).
  • Drink alcohol in moderation because there is evidence to suggest that alcohol may increase the risk of developing melanomas.

    What the doctor may do

  • Perform a skin biopsy to confirm the diagnosis and stage the melanoma. The pathologist reading the microscopic slide also measures the thickness of the melanoma and the level of penetration (known as Clark's level). Thin melanomas that are less than 0.76mm thick are unlikely to cause fatalities.
  • The doctor may need to remove a wider area of skin around the melanoma.
  • In more advanced cases, the lymph glands draining the area may also need to be removed.
  • Chemotherapy or immunotherapy may be used in very advanced cases.
  • Long-term follow-up is necessary.

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MELASMA

Melasma or chloasma is a blotchy type of facial pigmentation, most commonly seen in women.

    Causes

  • Unknown.
  • Pregnancy (hence, its other name "mask of pregnancy") and the birth control pill may precipitate it.
  • Sun-exposure makes melasma worse.
  • Racial factors may be important as melasma is more common among darker-skinned persons.
  • Inheritence may also play a role as melasma tends to run in families.

    Symptoms

  • Yellow brown to black blotches on the face, especially the cheeks, forehead, nose and upper lip.
  • The blotches usually darken on exposure to the sun.
      Melasma.
    Click on image for larger view
    Key point
  • Melasma may sometimes be due to a phototoxic contact dermatitis to perfumes found in after-shave lotions (especially musk-ambrette) and scented toiletries.

    What you can do

  • Nothing since it is a cosmetic problem.
  • Use cosmetics to camouflage the pigmentation.
  • Protect the skin against the sun (see sun protection).

    What the doctor may do

  • Prescribe lightening creams containing hydroquinone alone or a combination of hydroquinone and tretinoin with or without a steroid.
  • Perform superficial or medium depth chemical peels.
  • Remove the aggravating cause eg., discontinue the birth control pill.
  • Counsel you on sun protection.

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MILARIA

Milaria (prickly heat or heat rash) is common in children, adolescents and young adults living or working in hot humid environments. It is more common during the first few weeks of life because the sweat ducts have not fully developed and get blocked easily.

    Cause

  • Milaria occurs when sweat cannot evaporate but is absorbed into the skin causing it to swell and block the opening of the sweat duct.

    Symptoms

  • The mild form, milaria crystallina appears as tiny, clear blisters.
  • The more severe form appears as pin-head size blisters or pusheads surrounded by redness on the chest and back where there is a higher concentration of sweat glands and on areas of the skin where the surfaces touch each other such as the neck, under the arms, in the groins, in the skin folds of plump babies and obese adults. The inflamed variety is called milaria rubra (red papules) or milaria pustulosa (when there are pusheads).
  • Itching and a prickly burning sensation may occur in milaria rubra and milaria pustulosa.

      Milaria rubrum.
    Click on image for larger view

    Complications

  • Milaria interferes with sweating and the ability of the body to cool itself. Heat stroke may develop if milaria is extensive.
  • Secondary infection by bacteria or fungi..

    What you can do

  • The aim is to reduce excessive sweating and humidity:
  • Wear light cotton clothing and loose clothing.
  • Avoid high temperatures and humidity. Use fans or air conditioning.
  • Limit physical activity if possible.
  • Take cool baths or showers regularly.
  • Dry well.
  • Calamine lotion may be helpful.
  • Taking vitamin C, 1g daily may be helpful.
  • Consult a doctor if there is no improvement after a week.

    What the doctor may do

  • Confirm the diagnosis.
  • Prescribe mild topical steroids.
  • Treat the complications.

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MOLES OR MELANOCYTIC NAEVI

Melanocytic naevi (naevi is plural for naevus) or common moles are usually not present at birth but appear in later life, especially during puberty and pregnancy. Most adults have on average about 20 moles. Moles that appear at birth are called congenital moles.

    Cause

  • Non-cancerous proliferation of melanocytes (pigment cells).
Symptoms
Melanocytic naevi may be flat or raised, hairy or hairless and their colours vary from skin coloured to pink, brown or black. However, they all show symmetry, regular outlines and are evenly coloured. Any departure from this should be viewed with suspicion (see ABCD signs). The different types of moles include:
  • Junctional naevi
    • These are flat and dark brown or black.
     
  • Intradermal naevi.
    • These are elevated, skin coloured, brown or black and may be smooth or warty.
     
  • Compound naevi.
    • These are usually elevated, dome-shaped, skin-coloured, brown or black. and may have hairs growing out of them.
     
  • Halo naevi (Sutton's naevi, leukoderma acquisitum centrifugum)
    • These are moles that have a pale halo around them. They usually occur in children and young adults.
     
  • Blue naevus
    • These are deep moles which are blue because the pigment lies deeper in the skin. They usually occur in children and young adults.
     
  • Congenital naevi.
    • These are moles that appear at birth. They may be hairy and may quite large, sometimes covering a large segment of the skin or an entire limbs.
     
  • Dysplastic naevi (atypical moles)
    • These are moles that show atypical features (see American Academy of Dermatology's ABCD signs).

      Compound mole.
    Click on image for larger view

    Complications

  • Most moles do not become cancerous. However, there is a higher cancer risk in large congenital naevi and in dysplastic naevi and this is why people with these moles need to be closely followed up by a dermatologist (skin specialist). Look out for the following:

      ABCD signs as recommended by the American Academy of Dermatology:

     
    • Asymmetry which means one side does not match the other.
    • Borders that are irregular.
    • Colour variation within the lesion such as various shades of red and blue mixed with areas of black, white or brown.
    • Diameter over 6mm.
      Change in a pre-existing mole such as:
       
    • Bleeding, oozing, crusting or ulceration.
    • Pain, tenderness or itching.
    • Inflammation around the mole.
    • Nodule developing in the centre.

    What you can do
  • You should consult a doctor if any of the above changes occur.
  • See a doctor if you want a mole removed for any reason.
  • Do not irritate the mole or pluck hairs from a mole. Cut the hairs off carefully if you want to.
     
    What the doctor may do
  • Confirm the diagnosis.
  • Remove suspicious looking moles.
  • Excise for cosmetic reasons.

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MOLLUSCUM CONTAGIOSUM

Molluscum contagiosum (water wart) is a viral infection of the skin that affects children, especially those with atopic dermatitis and young adults. Infection is transmitted by skin-to-skin contact including sexual intercourse (adults cases).

    Cause

  • Pox virus. Infection is transmitted by skin to skin contact in children or during sexual contact in adults.

    Symptoms

  • Pearly-white or skin coloured papules (pimply bumps), often with central pit or depression.
  • Size between 2 - 5 mm.
  • Tendency to occur in groups or in lines along scratch marks.
  • Occurs on the genitals of adults (where it is usually sexually transmitted) or anywhere on the face and body of children.
      Molluscum contagiosum.
    Click on image for larger view
    What you can do
  • You should consult a doctor. Although, molluscum contagiosum can clear on their own, this may take several months to 2 years and there is a risk of transmitting infection to other people.
  • Do not pick or scratch as this causes the infection to spread to other areas.

    How the doctor can help

  • Treat using electrosurgery, liquid nitrogen, curettage, application of trichloroacetic acid or cantharidin, tretinoin (Vitamin A acid) cream and salicylic acid.

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MONGOLIAN SPOT

This is a type of pigmented birthmark that occurs at birth. It is seen more commonly in Asian and black babies.

    Cause

  • Benign proliferation of melanocytes (pigment cells) within the dermis.

    Symptoms

  • Blue-black patch on the buttocks or near the base of the spine (may be misdiagnosed as child abuse).

    What you can do

  • Nothing as they will disappear on their own.
  • See a doctor to confirm the diagnosis.

    What the doctor may do

  • Confirm the diagnosis.
  • Reassure you that it will disappear with time.

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MUCOUS CYST

This is a type of cyst that usually occurs in the lower lip of young and middle-aged adults.

    Cause

  • Blockage or rupture of the salivary gland.
     
    Symptoms
  • Bluish coloured cyst, usually on the inner surface of the lower lip.

      Mucous cyst.
    Click on image for larger view

    What you can do

  • ou should consult a doctor.
  • Do not pierce or bite the cyst.

    What the doctor may do

  • Remove using electrosurgery, carbon dioxide laser or by surgical excision. Recurrences are quite common.
  • Incision and draining the jelly-like fluid inside the cyst. This is usually temporary as the cyst often recurs.

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MYCOSIS FUNGOIDES

This is a type of lymphoma (lymphatic cancer) that affects the skin. It is also called cutaneous T-cell lymphoma CTCL.

    Cause

  • A type of cancer arising from the T-lymphocytes (a special type of white blood cell).

    Symptoms

  • Persistent red scaly patch which may be mistaken for eczema or psoriasis.
  • Over time, the patch becomes thicker and developes into a plaque or becomes nodular and may even ulcerate.
  • Mycosis fungoides may affect any part of the body but is more common on the back, buttocks and shoulders.
  • There may or may not be itching.
  • Usually affects middle-aged and elderly individuals.
  • May involve the whole body as an erythroderma. This type of mycosis fungoides is called Sezary syndrome and may be associated with abnormal white cells known as Sezary cells in the blood. Sezary syndrome is considered to be the leukaemic stage of mycosis fungoides..

      Mycosis fungoides.
    Click on image for larger view

    Complications

  • May spread internally to other organs.
  • May be fatal.

    What you can do

  • You should consult a doctor.

    What the doctor may do

  • Perform a skin biopsy to confirm the diagnosis.
  • Perform tests to exclude other organ involvement
  • Treat with UV-B or PUVA, anti-cancer drugs, nitrogen mustard.

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