Acitretin is a type of drug called a retinoid. Retinoids are closely related to Vitamin A and work by slowing down cell growth in the skin. 

• Acitretin - printable version

Acne is a very common skin condition identified by the presence of comedones (blackheads and whiteheads) and pus-filled spots (pustules). It usually starts during puberty. Acne ranges from a few spots on the face, neck, back and chest, which most teenagers will have at some time, to a more severe problem that may cause scarring and reduce self-confidence. For most, it tends to go away by the early to mid twenties, but it can go on for longer. Acne can also develop for the first time in people in their late twenties and beyond.

Occasionally, young children will develop blackheads and/or pustules on the cheeks or nose.

• Acne - printable version

Actinic keratoses are areas of sun-damaged skin found predominantly on sun-exposed parts of the body, particularly the forearms, backs of the hands, face, ears, bald scalp and the lower legs. They may also occur on the lips. The terms actinic andsolar arefrom the Greek and Latin respectively, meaning ‘sunlight-induced’. The term keratosis refers to thickened skin.

• Actinic Keratoses - printable version

The term 'actinic prurigo’ is the term used for a rare (less than 1 in 1,000) type of skin sensitivity induced by sunlight (photosensitivity); 'actinic' is Greek for 'sunlight', ‘pruritus’ is the medical term for itching, and ‘prurigo’ is a related word which describes the changes that appear in the skin after it has itched and been scratched for a long time. In actinic prurigo the skin becomes firm, raised and itchy on the areas of the skin surface which are exposed to the sun.

• Actinic prurigo - printable version

Adalimumab is a powerful drug that has been specially designed to mimic normal human molecules, and for this reason it is classed as a ‘biological’ drug. It reduces inflammation by inhibiting the activity of a chemical ‘cytokine’ in the body called ‘tumour necrosis factor alpha’ (TNF-alpha). 

• Adalimumab - printable version

Alitretinoin (brand name Toctino) belongs to a group of drugs called retinoids, which are closely related to vitamin A. It works by reducing skin cell turnover and also helps to reduce skin inflammation.

• Alitretinoin - printable version

Alopecia is a general term for hair loss. Alopecia areata is a common cause of non-scarring (does not cause scarring to the scalp) hair loss that can occur at any age. It usually causes small, coin-sized, round patches of baldness on the scalp, although hair elsewhere such as the beard, eyebrows, eyelashes, body and limbs can be affected. In some people larger areas are affected and occasionally it can involve the whole scalp (alopecia totalis) or even the entire body and scalp (alopecia universalis).

It is not possible to predict how much hair will be lost. Regrowth of hair in typical alopecia areata is usual over a period of months or sometimes years, but cannot be guaranteed. The chances of the hair regrowing are better if less hair is lost at the beginning. Most people, with only a few small patches get full regrowth within a year. If more than half the hair is lost then the chances of a full recovery are not good. The hair sometimes regrows white, at least in the first instance. Most people get further attacks of alopecia areata. In alopecia totalis and alopecia universalis, the likelihood of total regrowth is less.

• Alopecia areata - printable version

Apremilast is an oral medication which works by inhibiting (stops it from working as it usually does) an enzyme known as phosphodiesterase inhibitor (PDE4). PDE4 controls the inflammation process in the skin. Reducing or controlling the inflammation in the skin can lead to improvement of symptoms in people with psoriasis. 

• Apremilast

Atopic eczema is a common skin condition and may start at any age, but the onset is often in childhood: 1 in every 5 children in the UK are affected by eczema at some stage.

The term ‘atopic’ is used to describe a group of conditions, which include asthma, eczema and hay-fever¹. These conditions are all linked by an increased activity of the allergy reaction of the body’s immune system. ‘Eczema’ is a term which comes from the Greek word ‘to boil’ and is used to describe red, dry, itchy skin which sometimes weeps, blisters, crusts, scales and thickens.

• Atopic eczema - printable version

An Atypical Fibroxanthoma (AFX) is an uncommon type of skin cancer, accounting for less than 0.2 % of all skin cancers. It occurs mainly on the head or neck of older people, usually after the skin has been damaged by prolonged exposure to sunlight.

• Atypical fibroxanthoma - printable version

Atypical mole syndrome is a disorder of the skin which is seen in approximately 2% of the population. It is defined when an individual has more than 50 moles composed of melanocytes (pigment producing skin cells) present on their skin, and three or more are atypical (unusual) in their appearance, such as their size, shape or colour. An atypical mole is one greater than 5 mm in diameter, often with flat and raised areas, oval rather than round, and with some colour variation.

Solitary atypical moles are individually benign moles with a low risk of progression to melanoma (a type of skin cancer). However, people with multiple atypical moles (atypical mole syndrome) are considered to have a higher risk (increased 7 to 10-fold) of developing melanoma compared to the general population, due to the presence of atypical moles especially if some of these moles are on the scalp, buttocks, or feet. The risk is increased further if one or more first or second degree relatives (i.e. a close blood relative including parents, full siblings or children, or a blood relative including grandparents, grandchildren, aunts, uncles, nephews, nieces or half-siblings, respectively) have been diagnosed with malignant melanoma; this combination is known as familial atypical mole syndrome.

• Atypical mole syndrome - printable version

• Azathioprine has been available since the 1960s and was initially developed to stop the body from rejecting transplanted organs, such as kidneys.
• It is now also used to treat a wide range of illnesses.
• It works by suppressing the body’s own immune system, either by itself or in combination with other drugs.
• Azathioprine is not a steroid and is considered to be safer for longer term use than high doses of steroid tablets.

• Azathioprine - printable version

A basal cell carcinoma (BCC) is a type of skin cancer. There are two main types of skin cancer: melanoma and non-melanoma skin cancer. BCC is a non-melanoma skin cancer, and is the most common type (greater than 80%) of all skin cancer in the UK. BCCs are sometimes referred to as ‘rodent ulcers’. 

• Basal cell carcinoma - printable version

‘Naevus’ is the Latin word for birthmark. It is called Becker’s after the name of the American Dermatologist that described it.Becker’s naevus is sometimes called ‘Becker's melanosis’ or ‘pigmented hairy epidermal naevus’.

Becker’s naevus usually develops in the second or third decade of life. It can occur in all skin types and is more common in boys than girls. Although most commonly people will only have one Becker’s naevus, it is possible to have more.

• Becker's naevus - printable version

Blue rubber bleb naevus syndrome has also been called ‘Bean syndrome’ after Dr William Bean, who described it. It is caused by the congenital development of multiple venous malformations in the skin, soft tissues and gastrointestinal tract (intestine).

A ‘syndrome’ is a group of signs and symptoms that occur together. ‘Naevus’ is Latin for ‘birthmark’. The ‘blue rubber blebs’ are small areas of blue mis-shaped veins with a rubber-like feel.

In some people, blebs are only seen in the skin. They can also occur in any other part of the body, most commonly the intestine.

• Blue rubber bleb naevus - printable version

A boil, or furuncle, is an abscess (infection) of the skin or in the deep part  hair follicles. The infection is usually caused by bacteria called Staphylococcus aureus (S. aureus). Occasionally the infection may spread into the surrounding tissues (cellulitis) and can cause fever and a feeling of being unwell. When several boils form close together and join, this is known as a carbuncle. Sometimes rarer types of S. aureus: Methicillin resistant Staphylococcus aureus (MRSA) and Panton-Valentine leukocidin (PVL), can cause boils. PVL may cause larger and more painful boils (see Patient Information Leaflet on PVL Staphylococcus Aureus (PVL-SA) skin infection).

The bacteria causing the boil can occasionally spread from one part of the body to another and from one person to another by skin-to-skin contact and from clothing and towels which have been contaminated with pus from the boil. This is especially true when boils are caused by the PVL strain of S. aureus bacteria. Boils are common in teenagers and can affect boys more often than girls. Sufferers of boils do not usually have a problem with their immune system, but boils can be more severe in patients with a suppressed immune system. Boils are more common in patients with diabetes and those who are overweight. 

• Boils - printable version

Squamous cell carcinoma in situ, often called Bowen’s disease, is a growth of cancerous cells that is confined to the outer layer of the skin. It is not a serious condition, and its importance rests on the fact that, very occasionally, it can progress into an invasive skin cancer known as squamous cell carcinoma (see Patient Information Leaflet on Squamous Cell Carcinoma for further information). For this reason, dermatologists usually treat, or at least monitor, Bowen's disease. Squamous cell carcinoma in situ, often called Bowen’s disease, is a growth of cancerous cells that is confined to the outer layer of the skin. It is not a serious condition, and its importance rests on the fact that, very occasionally, it can progress into an invasive skin cancer known as squamous cell carcinoma (see Patient Information Leaflet on Squamous Cell Carcinoma for further information). For this reason, dermatologists usually treat, or at least monitor, Bowen's disease.

• Bowen's Disease - printable version

Brodalumab is a biologic medicine that has been designed to treat psoriasis. It works by specifically targeting a chemical messenger (known as a ‘cytokine’) in the body called ‘interleukin-17A’ (IL-17A). We know that IL-17A is one of the main causes of inflammation in psoriasis, and by blocking it brodalumab can improve symptoms of psoriasis. 

• Brodalumab

There are two types of topical calcineurin inhibitors called tacrolimus ointment (Protopic 0.03% and 0.1%) and pimecrolimus cream (Elidel). They are classified as immunomodulating agents.  This means that they act on the immune system to reduce skin inflammation. Both tacrolimus and pimecrolimus block a chemical called calcineurin which activates inflammation in the skin and causes redness and itching of the skin.

• Calcineurin inhibitors - printable version

Capillaritis, also known as pigmented purpura, is a skin condition in which red and brown dots and patches appear on the skin. It usually affects the lower legs and does not cause any symptoms. It is more commonly seen in adults though can affect children too.

• Capillaritis

The “vulva” is the term used to describe the visible part of the female genitalia which includes the inner and outer “lips” (labia) and clitoris.

• Care of vulval skin - printable version

Erysipelas and cellulitis are common infections of the skin. Erysipelas is a superficial infection, affecting the upper layers of the skin, while cellulitis affects the deeper tissues. They can overlap, so it is not always possible to make a definite diagnosis between the two. 

• Cellulitis and erysipelas - printable version

Alopecia is a general term for hair loss. Central centrifugal cicatricial alopecia (CCCA) is a type of permanent hair loss that often starts on the top of the scalp and spreads outwards. Other names for CCCA include ‘Follicular Degeneration Syndrome’ and ‘Hot-comb alopecia’.              

CCCA is the most common form of permanent hair loss seen in women of African descent, mainly beginning around the ages of 30-40 years. Very occasionally, it may also affect men.

• Central centrifugal cicatricial alopecia - PRINTABLE

Chondrodermatitis nodularis is inflammation of the skin of the ear. This Latin/Greek name literally means an inflammation both of the cartilage (chondro-) and of the skin (-dermatitis) causing a bump (a nodule, hence nodularis).

It is common and harmless, but can be tender when touched. 

• Chondrodermatitis nodularis - printable version

The term ‘chronic actinic dermatitis ‘or ‘CAD’ is used to describe an unusual type of eczema or dermatitis that is caused by abnormal skin sensitivity to sunlight (photosensitivity). CAD usually lasts for several years. ‘Chronic’ means the condition can last a long time, ‘Actinic’ means sunlight is involved and ‘dermatitis’ means inflammation of the skin.

• Chronic actinic dermatitis - printable version

Paronychia is a common infection of the skin around the finger or toenails (the nail folds). There are two types - ‘acute paronychia’ develops quickly and lasts for a short period of time; and ‘chronic paronychia’ develops slowly, lasting for several weeks and often comes back. Chronic paronychia is not caught from someone else. 

• Chronic paronychia - printable version

Like penicillin, ciclosporin is a substance produced by a fungus. Ciclosporin was found to suppress the immune system. It was initially developed for suppressing the immune system of transplant patients to prevent them from rejecting their transplanted kidneys and other organs. It was subsequently found to help patients with a wide range of diseases caused by immune reactions. 

• Ciclosporin - printable version

Colchicine is an extract of the plant Colchicum autumnale (autumn crocus). It has been used as a medicine since ancient times.

Colchicine changes the response of the immune system. It has been found to be helpful in conditions where a person has too many neutrophils (a type of white blood cell) in the skin.

• Colchicine - printable version

Congenital dermal melanocytosis is a common, harmless, pigmented birthmark. It is sometimes also called lumbrosacral dermal melanocytosis, and is sometimes still referred to by its old name of a Mongolian Blue Spot.   It is usually seen at birth or shortly afterwards. It typically disappears before the age of 6. 

• Congenital dermal melanocytosis - printable version

Congenital erythropoietic porphyria (CEP), also called Günther disease after the doctor who first described it, is the rarest of the porphyrias. It is estimated that about 1 in every 2 or 3 million people are affected by CEP, which affects males and females equally, and occurs in all skin types.

The word ‘congenital’ means acondition that exists birth and often before birth, or that develops during the first month of life; ‘erythropoietic’ means associated with red blood cells and their formation.

The porphyrias are a group of inherited disorders in which there is an abnormal increase in production of substances in the body called porphyrins. Porphyrins are very important as they form haemoglobin that carries oxygen around the body in the red blood cells. The production of haemoglobin involves a chain of reactions in which one porphyrin is converted to another. If there is a block in the chain of reactions, there will be a build-up in the body of a specific porphyrin depending on where the block occurs. Porphyrins in high concentration are damaging to tissues. The problems caused by the different porphyrias are dependent on which particular porphyrin that accumulates. In the case of CEP, there is a build-up of one of these porphyrins called porphyrinogen in the bone marrow, blood and urine, and this leads to the symptoms and signs of CEP.

• Congenital erythropoietic porphyria - printable version

Dermatitis (also known as eczema) describes a type of inflammation of the skin. Contact dermatitis (contact eczema) is a term used when this inflammation is caused by direct or indirect skin contact with something in a person’s environment.

• Contact dermatitis - printable version

The term ‘cryotherapy’ literally means ‘treatment using low temperature’ and refers to the removal of skin lesions by freezing them. The most common product used by doctors is liquid nitrogen.

• Cryotherapy - printable version

Amyloidosis or ‘amyloid’ is group of rare diseases in which abnormal proteins, accumulate in various organs including the skin. The name ‘amyloid’ was given to the condition over 150 years ago because the deposits looked like starch under the microscope. (In Latin amylum = starch).

In primary localised cutaneous amyloidosis (PLCA) amyloid deposits only occur in the skin. The exception to this is a rare disease called nodular amyloid, which can be associated with amyloid deposits in other body organs and myeloma (a form of bone marrow cancer).

PLCA is uncommon in Europeans and occurs more frequently in people who originate from South-East Asia, South America and the Middle East. It usually starts in adult life and tends to persist for many years. 

There are three main forms of PLCA: Macular amyloidosis, lichen / papular amyloidosis and Nodular amyloidosis (the rarest form).

• Cutaneous amyloidosis - printable version

Vasculitis is a term referring to inflammation of blood vessels; these may be arteries, veins or both, and can affect any part of the body. When vasculitis affects small or medium sized blood vessels in the skin, it is known as cutaneous vasculitis. Occasionally cutaneous vasculitis can be a sign of inflammation occurring in other organs (a systemic vasculitis) and further investigation may be required for a full diagnosis.

• Cutaneous vasculitis - printable version

CCS is a rare genetic condition which causes patients to develop multiple benign skin tumours on the scalp and body. The benign skin tumours may be called cylindromas, spiradenomas or trichoepitheliomas, and some patients may have a combination of these tumours. Cylindromas are benign skin tumours that arise from hair follicles, which present as pink lumps on the scalp and trunk. Spiradenomas are benign skin tumours that are often painful, and can have a blue or black colour, and are related to cylindroma. Features of cylindroma and spiradenoma can often be found in a single skin lump in patients with CCS. Trichoepithelioma are skin-coloured small lumps often seen on the skin around the nose.

• CYLD cutaneous syndrome - printable version

By definition, cyst is a closed sac that has two main features:

•       A lining

•       Contents that are liquid or semi-solid

The lining. Differences between the lining of epidermoid and pilar cysts can be seen under the microscope:

•       The lining of an epidermoid cyst looks like the epidermis (the outermost layer of cells in the skin)

•       The lining of a pilar cyst is made up of cells like those found in the roots of hairs

The contents. Both types of cyst contain a cheesy material, looking rather like white toothpaste. This is made of keratin - the material that makes up hair and the outer layer of the skin.

In the past, pilar and epidermoid cysts were wrongly known as ‘sebaceous’ cysts but this term should be used only for a quite different and much less common type of cyst that is filled with a clear oily liquid made by sebaceous (grease) glands.

Epidermoid and pilar cysts are common, not cancerous, and not contagious.

• Epidermoid and pilar cysts - printable version

Dapsone is a sulphonamide antibiotic. It is available only on prescription. It acts as an anti-inflammatory drug and has been used successfully as a treatment for several skin conditions such as dermatitis herpetiformis, pyoderma gangrenosum, Sweet’s syndrome and vasculitis for many years. It can, under supervision of your dermatologists, also be used for other inflammatory skin conditions that are not mentioned here if none of the standard treatments are effective.

• Dapsone - printable version

It is a rare inherited skin condition, estimated to affect 1 to 4 people per 100,000 of the population and is characterised by a change in the way skin cells (keratinocytes) stick together within the upper layer of the skin (epidermis). This leads to changes in the skin and nails, and sometimes inside the mouth can be affected. Other names for Darier disease include Darier-White disease and Keratosis Follicularis.

• Darier's disease - printable version

Dermatitis herpetiformisis a rare, very itchy and persistent blistering skin condition, affecting between 0.4 and 3.5 people per 100,000 of the European population. It typically affects Caucasians aged between 15-40 years and is more common in men, but can occur in all age and racial groups.

• Dermatitis herpetiformis - printable version

A dermatofibroma is a common overgrowth of the fibrous tissue situated in the dermis (the deeper of the two main layers of the skin). It is benign (harmless) and will not turn into a cancer. Whilst dermatofibromas are harmless, they can be similar in appearance to other concerning skin tumours. It is therefore important to see a health professional for a diagnosis.

• Dermatofibroma - printable version

DFSP is a very rare type of skin cancer. It usually occurs on the trunk, often the chest and shoulders; however, it can also affect the limbs, head and neck and rarely the genitalia. It starts in the deep layer of the skin (the dermis) and can spread to surrounding structures such as fat and muscle. Although it grows very slowly, it can become quite large. It can often be completely removed with a wide margin of normal tissue, or with a specialised form of surgery called Mohs surgery. DFSP can come back even if completely removed by surgery. It is very rare for DFSP to spread to other parts of the body (occurring in approximately 5% of cases).

• Dermatofibrosarcoma protuberans - printable version

Dermatomyositis is a rare condition that causes inflammation in both the skin and the muscles. The word comes from the Latin for skin (dermis), muscles (myos) and inflammation (-itis). In rare cases, only the skin is affected and not the muscles.

• Dermatomyositis - printable version

A digital myxoid cyst (sometimes called a mucous cyst) is a non-cancerous swelling that occurs on the fingers or, sometimes, the toes.The cyst is often connected to the lining of the finger or toenail joint, and is usually located between the joint and the nail.

Digital myxoid cysts are not contagious and are not a form of skin cancer.

The term cyst is from the Greek kystis meaning a bag or pouch; myxoid and mucoid refer to the jelly-like contents. Digital derives from the Latin digitus, meaning finger or toe. A small number of people might develop these because of excessive repetitive finger motion.

• Digital myxoid cyst - printable version

Fumaric acid esters (FAEs) are chemical compounds that have been used as a treatment of psoriasis for over 30 years. The licensed FAE for treatment of moderate to severe plaque psoriasis in the UK is Skilarence® which contains dimethylfumarate (DMF), the main active ingredient.

• Dimethyl fumarate (Fumaric acid esters ) - printable version

• Discoid eczema - printable version

The term ‘lupus erythematosus’ is applied to a group of related disorders. ‘Discoid’ lupus erythematosus (DLE) is one of these often confined to the skin and is not commonly associated with symptoms from other organs. It is characterised by persistent, localised, red or pink scaly patches of skin most often on the head and neck, including the scalp and ears. Less often the rash can be more generalised.  Uncontrolled inflammation may lead to permanent skin damage e.g. scarring hair loss/alopecia, darker or lighter pigment changes or scarring.

• Discoid lupus erythematosus - printable version

Dissecting cellulitis of the scalp is a rare inflammatory scalp condition. Pus-filled spots and lumps develop with subsequent hair loss over the affected area. Hair loss is permanent due to the inflammation which destroys the hair follicles and leaves scar tissue.

The condition is occasionally referred to as perifolliculitis capitis abscedens et suffodiens. It usually affects darker-skinned adult men, especially those of Afro-Caribbean origin, but can affect any race, sex or age.

• Dissecting cellulitis - printable version

DSAP is a skin condition with multiple, dry, scaly rings, each measuring up to 1 cm (1/2 inch) across. They are found mainly on the forearms and legs, in sun-exposed sites. It is sometimes confused with actinic keratosis which is also caused by sun exposure (See Patient Information Leaflet on Actinic Keratoses); however, actinic keratosis is more likely to arise on the face and hands.

DSAP is twice as likely to develop in women compared with men and is more common in lighter skin type. Itnormally develops between 30-50 years of age. It is not contagious.

There are multiple other types of porokeratosis, which affect different age groups or present in slightly different ways.

• Disseminated superficial actinic porokeratosis - printable version

Dupilumab is a biologic medicine that has been designed to treat eczema. It works by reducing inflammation. It works on chemical messengers (known as a ‘cytokines’) in the body called ‘interleukin-4’ (IL-4) and ‘interleukin-13’ (IL-13).

• Dupilumab - printable version

Dystrophic epidermolysis bullosa (DEB) is a rare inherited skin disorder. The skin of people with DEB is more fragile than normal. Minor injury causes blisters or ulcers that may be slow to heal and often leave scars. DEB can be mild, but it can also be severe, affecting the mouth, oesophagus (gullet), eyes and nails in addition to the skin.

Dystrophic epidermolysis bullosa (DEB) is divided into two main types depending on how it is inherited: recessive dystrophic epidermolysis bullosa (RDEB) and dominant dystrophic epidermolysis bullosa (DDEB)..

There are other forms of inherited epidermolysis bullosa (EB), including epidermolysis bullosa simplex, junctional epidermolysis bullosa and Kindler Syndrome. These are all distinct skin diseases so people who have DEB do not develop other types of epidermolysis bullosa at a later date.

• Dystrophic epidermolysis bullosa - printable version

Eccrine porocarcinoma is a rare type of skin cancer involving a type of sweat gland called the eccrineglands. Eccrine sweat glands are present in theskin, with the highest density on the palms, soles,face and scalp.

Eccrine porocarcinoma is typically a slow-growing tumour which is more common in those who are over 60 years of age, and occurs equally in men and women. It can sometimes spread to internal organs in the body.

• Eccrine porocarcinoma - printable version

Atopic eczema is a very common skin condition due to skin inflammation. It may start at any age but the onset is often in childhood. 1 in every 5 children in the UK is affected by eczema at some stage. It may also start later in life in people who did not have AE as a child.

The term ‘atopic’ is used to describe a group of conditions, which include asthma, eczema and hay-fever and food allergy. These conditions are all linked by an increased activity of the allergy side of the body’s immune system. ‘Eczema’ is a term which comes from the Greek word ‘to boil’ and is used to describe red, dry, itchy skin which can sometimes become weeping, blistered, crusted, scaling and thickened.

Eczema herpeticum is a potentially serious viral infection which can spread to large areas of the skin. It most commonly affects people with atopic eczema but may also affect those with other inflammatory skin conditions. 

• Eczema herpeticum - printable version

Epidermolysis bullosa (EB) simplex is a rare inherited disorder in which the skin is fragile and blisters at sites of rubbing. It is mild in the usual form; blisters tend to be confined to the palms and soles, and are most troublesome during warm weather. In other types the blistering may be more generalised and occasionally blisters arise in the mouth. The most severe form is called generalised severe EB simplex (Dowling-Meara) and those affected have more widespread blistering which occurs throughout the year.

EB simplex is different from other types of EB which include junctional, dystrophic and Kindler forms; if you have EB simplex then you will not go on to develop these other types. EB simplex is not an infection, it is not contagious, and it is not due to an allergy.

• Epidermolysis bullosa simplex - printable version

Erosive (presenting with superficial ulcerations/erosions) pustular(pus forming) dermatosis(skin problem) is a long-term skin disease of scalp and legs. Women develop it three times more often than men. EPD most commonly develops in the elderly.

• Erosive pustular dermatosis - printable version

Erythema multiforme is usually mild - 'erythema multiforme minor' – with only skin involvement, and clearing up in days to weeks. There is also a rare but more severe type, 'erythema multiforme major', which has similar skin features to EM minor, but additionally there is involvement of one or more mucosal membrane (e.g. the lips, the inside of the mouth, the windpipe, the gullet, the anus or genital area, and the eyes) and usually some associated symptoms, such as fever or joint pain.

• Erythema multiforme - printable version

Erythema Nodosum (EN) is a skin condition that is characterised by painful red, round lumps which typically appear on the shins and around the ankles, and less commonly the thighs and forearms. It can occur at any age, in both sexes, and in anyone.These lumps tend to heal to leave a bruise-like appearance. It usually goes away by itself, and rarely may recur, but it can be a sign of something more serious. EN is more common among females and is more frequently observed between the ages of 25 and 40 years (1,2). In England the rate is about 2.4 cases per 10000 per year.

• Erythema Nodosum

Erythromelalgia is a rare condition. In ancient Greek, ‘Erythros’ means ‘red’ and ‘melalgia’ means pain in a limb.  It can cause episodes of intense burning pain, painful swelling and redness of the feet or hands. Sometimes the legs and arms can be affected, or, less often, other areas such as the ears or face. It usually affects both sides of the body. Females are more commonly affected than males. Erythromelalgia can occur in all ethnic groups. 

• Erythromelalgia - printable version

The word ‘erythropoietic’ means associated with red blood cells (‘erythro-’) and their formation (‘-poietic’). The porphyrias are a group of uncommon disorders caused by something going wrong with the production of chemicals known as porphyrins. These chemicals are the building blocks of haem, which, when combined with a protein (globin), forms haemoglobin, the material in red blood cells that carries oxygen round the body. In the case of EPP and XLDPP, there is a build-up of one of these porphyrins (protoporphyrin IX) in the blood, especially in the red blood cells. This leads to a sensitivity to sunlight.

• Erythropoietic protoporphyria and X-linked dominant protoporphyria - printable version

Etanercept is one of the first of a group of modern drugs called ‘biologics’ or ‘biologicals.’ Unlike ordinary drugs which can usually be made from chemicals in a test tube, biologics are complex molecules made by living cells. They are designed to mimic or change processes in the human body and are used to treat a range of diseases from cancer to arthritis.

Etanercept blocks the effect of tumor necrosis factor alpha (TNF-alpha) so it is called an ‘anti-TNF’ drug. TNF-alpha helps the body fight infection and cancer, but when over produced it can have harmful effects. Over-production of TNF occurs in several diseases including Crohn’s disease, psoriasis and inflammatory arthritis, so anti-TNF drugs have been as treatment.

• Etanercept - printable version

Extra-mammary Paget’s disease (EMPD) is a rare, slow-growing disease that is a pre-invasive form of skin cancer. It looks similar to a patch of eczema and usually affects skin in the genital area and around the anus. It is commonest in people aged over 50, with studies showing it peaks at around age 65. It is less common in males and in skin of colour.

Primary EMPD arises from cells in the skin, whilst secondary EMPD is due to spread of pre-cancerous or cancerous cells from nearby or distant organs/regions, most commonly the opening to the bladder (urethra), cervix, bladder or bowel.

Paget’s disease, in contrast, refers to the same type of changes occurring in the breast or nipple.There is no relation between EMPD and another disease called Paget’s disease of the bone.

• Extramammary Paget's Disease - printable version