Darier's disease | Dermatitis herpetiformis | Dermatofibroma | Dermatomyositis | Dermatosis papulosa nigra | Dermographism | Discoid eczema (go to nummular dermatitis) | Drug eruptions | Dry skin (go to xerosis) | Dysplastic naevi | Dysplastic moles (go to dysplastic naevi)

Darier's disease or keratosis follicularis is a rare inherited disorder of keratinisation (the way the skin cells accumulate keratin as they approach the surface). It usually begins around puberty and gets worse during adult life.

Cause

• Inherited as an autosomal dominant trait which means only one parent need to be affected and half the offsprings will inherit the defective gene and develop the disorder.

  Symptoms

• A rash comprised of greasy brown papules (pimply bumps) on the scalp. ears, face, neck and upper trunk.
• The affected areas tend to be moist and often give out a foul smell.
• Usually itchy.
• The rash is made worse by the sun.
• The palms and soles may be thickened.
• The insides of the mouth may also be affected by white patches.
• The nails may be fragile, short and relatively wide, notched and ridged and red and white linear streaks.

  Darier's disease. Click on image for larger view

  Complications

• Secondary bacterial infection.
• Kaposi's varicelliform eruption, a widespread viral infection caused by the herpes simplex virus.

  What you can do

• You should consult a doctor.
• Avoid excessive sun-exposure and use sunscreens.
• Wet compresses help to relieve itching and reduce crusting and odour.
• Take oral antihistamines to relieve itching.
  
  What the doctor may do
• Perform a skin biopsy to confirm the diagnosis.
• Treat the complications.
• Treat with oral retinoids such as acitretin.

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This is a rare disorder that is extremely itchy. It may affect any age group but is more common in young adults.

Cause

• Autoimmune disorder (self-allergy).

  Symptoms

• Clusters of tiny red papules (pimply bumps), blisters or small weals.
• Severe itching or burning so much so that all that remains to be seen are only broken skin.
• Usually occurs on the upper back, elbows, knees, buttocks, scalp, face and hairline.
• May be associated with gastric atrophy and gluten intolerance.

  Complications

• Males have a higher risk of intestinal lymphomas.

  What you can do

• You should consult a doctor.

  What the doctor may do

• Take a skin biopsy for routine histology and immunofluorescence (examination under a special immunofluorescence microscope).
• Perform a small bowel biopsy to detect gluten intolerance.
• Treat with dapsone or sulphapyridine.
• A gluten-free diet may help both the skin and gastrointestinal tract.

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Dermatofibromas or histiocytomas are harmless fibrous swellings usually found on the arms and legs, especially in women.

Cause

• Unknown, may be an unusual response to minor skin injury such as insect bites or minor skin trauma.

  Symptoms

• Skin coloured or yellow-brown pea-size papule (bump), often with a darker border.
• Feels firm or button-like when gripped between the thumb and index finger.
• It shows the dimple sign. This means is that it dimples when the skin surrounding it is squeezed inwards with the thumb and index finger.
• Painless.

  Dermatofibroma. Click on image for larger view

  What you can do

• You should consult a doctor.
• Request removal if it bothers you.

  What the doctor may do

• Confirm the diagnosis.
• Remove it surgically.

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This is an uncommon disorder affecting the skin and muscles.

Cause
There are two types of dermatomyositis:

 

• Autoimmune dermatomyositis which is caused by an autoimmune problem (self allergy) and
• Cancer associated dermatomyositis which is a sign of underlying cancer.

Symptoms

• Reddish-purple rash on the nose, cheeks, eyelids, knuckles, elbows and knees. Over time, the rashes spread to the neck, chest and upper back and shoulders.
• Flat-topped purplish papules (pimply bumps) on the knuckles or base of the nails.
• In chronic cases, the skin developes pigmentation, telangiectasias (broken capillaries) and varying degrees of thinning. This change is called poikiloderma.
• Photosensitivity or increased sensitivity to sunlight.
• Stiffness and weakness of the muscles of the shoulders and pelvis resulting in difficulty combing and walking up stairs.
• Weight loss.
• Fever.
• Symptoms related to the underlying cancer. Dermatomyositis may be a sign of nasopharyngeal cancer, a type of throat cancer that is more common among Chinese patients. Other cancers include breast, lung, gastrointestinal tract and ovarian cancers.

  Dermatomyositis. Click on image for larger view

  Complications

• Heart, lung and kidney problems may occur in autoimmune dermatomyositis and can be fatal.
• Death may result from the underlying cancer.

  What you can do

• You should consult a doctor.

  What the doctor may do

• Conduct a careful clinical examination and tests to confirm the diagnosis.
• Perform a skin biopsy, x-ray of chest, electrocardiogram (ECG), electromyography (which makes a tracing of the electrical activity of muscles) and blood tests.
• Special examinations to exclude underlying cancers.
• Prescribe oral steroids and immunosuppressive drugs.

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This condition is more common in the dark-skinned and is believed to be a form of seborrhoeic keratoses.

Cause

• Unknown.
• A familial or racial tendency has been observed.

  Symptoms

• Small black or brown papules (bumps) most frequently on cheeks and aound the eyes and temples.

  Dermatofibroma. Click on image for larger view

  What you can do

• Nothing as they are harmless.
• Consult a doctor for removal if they are cosmetically disturbing.

  What the doctor may do

• Treat with liquid nitrogen
• Destroy with the carbon dioxide laser.

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Dermographism is a type of urticaria that is induced by stroking the skin.

Cause

• Histamine and other chemicals are released when the skin is stroked, resulting in linear weals.

  Symptoms

• Itching is the first symptom followed by scratching which causes the scratch lines to swell or weal.
• Dermographism may be triggered by heat, rough textured fabrics, rough toweling and pressure on the skin.
• Dermographism may occur with other types of urticaria.
• Dermographism may continue for years.

  Dermographism. Click on image for larger view

  What you can do

• You should consult a doctor.
• Take antihistamines to reduce itching.
• Avoid rough fabrics, rough toweling and heat.

  What the doctor may do

• Prescribe antihistamines.
• Perform blood tests.

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Drug eruptions are one of the most common manifestations of drug allergy. They can mimic any skin condition and vary from mild rashes to severe reactions such as anaphylaxis, angioedema and Steven's Johnson's Syndrome. Diagnosis and management by a doctor is imperative.

Cause

• A person may develop an allergy to any drug taken by mouth or injected, including one that has been used before without problems. Drugs that more commonly cause rashes include penicillin and penicillin drugs such as ampicillin, amoxycillin, sulphur drugs, nonsteroidal anti-inflammatory drugs (NSAIDs), allopurinol (used to treat gout), phenytoin and carbemazepine (a drug used to prevent epilepsy), antimalarials such as chloroquine and hydroxychloroquine and gold (used for treating rheumatoid arthritis).

  Symptoms

• Measles-like (morbilliform) rashes.
• Urticaria.
• Erythema multiforme - target or bull's eye rashes, particularly noticeable on the palms and soles.
• Steven's Johnson's Syndrome - a severe type of erythema multiforme involving the mucous membranes lining the inside of the mouth, the eyes and genital area. Associated with fever and malaise (feeling of illness).
• Toxic epidermal necrolysis (TEN) - severe reaction in which the skin looks like it has been scalded. The skin comes off easily leaving large raw areas and the eyes, mouth and genital skin are often ulcerated. Fever, chills and malaise accompany the rash. Causes include sulphonamides, NSAIDs (nonsteroidal anti-inflammatory drugs), phenytoin (an anti-epileptic drug), allopurinol (used to treat gout) and penicillin. Death may result fluid and electrolyte imbalance, secondary infection and organ failure.
• Fixed drug eruptions - erythema multiforme-like rashes which occur in the same location each time the causative drug is taken.
• A lichen planus-like rash known as lichenoid drug eruption may be caused by drugs such as chloroquine (antimalarial drug), gold (sometimes used in the treatment of rheumatoid arthritis), captopril (used in the treatment of high blood pressure), streptomycin (an anti-tuberculosis drug), lithium (used in the treatment of manic-depressive states) and by colour developers.
• Erythroderma and exfoliative dermatitis.
• Blisters.
• Acneiform eruption - see acne vulgaris.
• Erythema nodosum - red, painful swellings on the legs.
• Pigmentation
• Purpura.
• Vasculitis
• Photosensitivity.
• Alopecia - see telogen effluvium
• Generalised pruritus..

  Fixed drug eruption. Click on image for larger view

  Morbilliform type of drug eruption. Click on image for larger view

  Complications

• Anaphylaxis and angioedema.
• Involvement of other organs such as the lungs, liver and kidneys with potentially serious consequences.

  What you can do

• Be aware of the possibility of drug eruptions when taking medicines. Stop the medicine and consult a doctor immediately if you develop symptoms of an allergy.
• If you have a history of drug allergy, apply for a medical alert card or tag (see prevention).

  Caution

• Some drugs are essential and suddenly stopping them can cause a worsening of the condition being treated. It is important, therefore, to see a doctor immediately after stopping the drug to see whether the skin condition is drug related and whether alternative medicines are available.

  Prevention

• Avoid the drugs you are allergic to.
• Apply for a medical alert card and carry it on your person all the time. The application form needs to be completed by your doctor, as well.
• Inform your doctor, dentist and pharmacist each time you see them.
• Inform your relatives about your drug allergy, as well.

  What the doctor may do

• Determine the cause through careful history taking, physical examination and laboratory tests.
• Remove the drug causing the allergy.
• Prescribe topical or systemic steroids and strong antihistamines.
• Some drug eruptions are mild and clear within two weeks of cessation and hospitalisation is not necessary.
• Hospitalise patients with severe reactions.

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Dry hair is caused by underactive sebaceous (oil) glands.

Cause

• Over-exposure to the sun, sunlamps, hair driers or curling irons.
• Underactive thyroid gland.
• Anaemia.

  Symptoms

• Coarse, dry, lustreless, sometimes brittle hair that may be difficult to comb and which tends to "fly-away".

  What you can do

• Hold the hair drier at least 6 inches away and dry hair partially, leaving it to dry hair naturally or better still, avoid using hair driers totally.
• Use mild shampoos for dry, damaged hair.
• Use conditioners.
• Comb hair gently with a wide toothed comb.
• Keep the hair short.

  What the doctor may do

• Exclude underlying medical problems that require treatment.

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Dysplastic naevi are atypical moles. They are atypical or different from common moles in two main ways. Firstly they are very numerous, sometimes more than 100 and secondly they look different and show the features mentioned in the ABCD guide of the American Academy of Dermatology (see below). The main significance of dysplastic naevi lie in the belief that there is an increased risk of malignant melanomas (cancerous moles) developing compared to common moles.

Cause

• Unknown or sporadic dysplastic naevi where there is no family history.
• inheritance as in the familial dysplastic naevi or dysplastic naevus syndrome where in addition to having dysplastic naevi, there is a family history of melanoma in two or more close relatives. Here the lifetime risk of developing melanoma is almost 100%. Familial dysplastic naevi have an autosomal dominant mode of inheritance which means that the offsprings of an affected parent has a 1 in 2 chance of being affected.

  Symptoms

• Large number of moles (sometimes in the hundreds) usually on the back, chest, abdomen and extremities.
• Moles show the characteristics mentioned in the American Academy of Dermatology's ABCD guide:-

  Signs of an atypical mole:

  • 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.

  Dysplastic naevi. Click on image for larger view

  Complications

• Development of melanoma. The lifetime risk of developing melanoma has been estimated to be 6% for sporadic dysplastic naevi and almost 100% for familial dysplastic naevi.

  What you can do

• You should consult a doctor.
• You must take protect your skin against sun-damage
• You should inform your close relatives to go for a skin check-up as dysplastic naevi may run in families.

  What the doctor may do

• Perform a careful examination and biopsy (remove for examination) the more suspicious moles.
• Follow up the patient every 6 months to a year for life. It is often not possible to remove all the moles because they are so numerous. Computerised mole mapping systems are used in more specialised centres to detect changes in moles.

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