Eruzioni cutanee

How are skin rashes described?

Skin rashes can be described in the following way:

• Redness of the skin (called eritema).

• Flat abnormally coloured areas of skin (called macules). Macules are often either red, dark red or purple, brown or white.

• Solid raised areas which are up to half a centimetre across (called papules).

• Solid raised areas which are more than half a centimetre across (called nodules).

• Areas of red raised skin (called plaques) e scales, which have a flaky silvery-white appearance.

• Reddish-purple lesions which do not fade with pressure (called porpora):
  

  • If less than one centimetre across then these are called petechiae.

  • If more than one centimetre across then they are called ecchymoses.

• Blisters: these are swellings of the skin containing fluid:

  • If a blister is less than half a centimetre across then it is called a vesicle. If filled with yellow fluid (pus) then it is called a pustule.

  • If a blister is larger than half a centimetre across it is called a bulla (plural is bullae).

What skin conditions cause itching?

Skin disorders that can cause itching include (please click the links to separate leaflets which provide further information):

• Pelle secca.

• Eczema.

• Contact dermatitis.

• Urticaria.

• Lichen planus.

• Psoriasi.

• Folliculitis.

• Prickly heat/heat rash.

What causes skin rashes?

Please click the links to separate leaflets which provide further information:

Red (erythema) but not scaly skin rash

• A skin infection called cellulite.

• An allergic reaction called orticaria.

• Reaction to a medicine you are taking.

• Ustioni.

• Eruzioni virali - eg, morbillo oppure rubella (German measles).

• Vasculitis. This is a condition involving inflammation of blood vessels, which may occur with various illnesses, including artrite reumatoide.

• Eritema nodoso. This is a condition which causes red rounded lumps (nodules), most commonly on the shins.

• Redness on the palms of your hands may be caused by liver disease, pregnancy or an ghiandola tiroidea iperattiva (ipertiroidismo).

• A red rash may occasionally be due to an inflammatory condition called lupus eritematoso sistemico, especially if it is on the cheeks.

Red (erythema) and scaly skin rash

• Psoriasi. This is a condition where there is inflammation of the skin.

• Eczema. This is sometimes called dermatitis and also involves inflammation of the skin. It may be caused by an allergy and is then called atopic dermatitis/eczema. This may happen in response to some plants - eg, poison oak or ivy.

• Dermatite seborroica (in adults). This is a type of skin rash sometimes called seborrhoeic eczema. In babies it is known as cradle cap.

• Fungal (or 'yeast') skin infection, such as il piede d'atleta, groin infection (tinea cruris), ringworm, scalp ringworm or infection with candida.

• Pitiriasi rosea. This condition is described as 'self-limiting' and the rash will clear itself naturally.

• Pitiriasi versicolor. This is a rash which is caused by a yeast-like germ.

• Lupus erythematosus.

• Lichen planus. This condition mainly affects the skin and causes an itchy rash.

Macules

• Red macules may be due to a reaction to a medicine or a eruzione cutanea virale - such as morbillo oppure rosolia - as well as other causes.

• A brown macule may be a mole but check with your doctor if a mole changes or you are concerned it might be a melanoma.

• A white macule may be due to a condition which causes pale patches of skin (called vitiligine) or a skin complaint with flaky discoloured areas (called pityriasis versicolor).

• If a macule is dark red or purple and does not fade when you put pressure on it then it is a purpura (see below) and you need to see a doctor urgently. This is because it could be a sign of meningite or blood infection (setticemia).

Papules

• Common causes of papules include cicatrici da acne, viral wart, seborrhoeic wart, mollusco contagioso, scabbia, morsi di insetto and skin tags.

• Other causes include psoriasi.

Purpura and petechiae

• These are dark red or purple and don't fade when you press them. You need to see a doctor urgently because there may be a serious cause that needs urgent treatment, such as meningococcal infection.

• However, common causes include injury to the skin or repeated coughing. More serious common causes include liver disease such as cirrosi.

• Less common causes include vasculitis (eg, Porpora di Henoch-Schönlein) or a low level of platelets in your blood (eg, porpora trombotica trombocitopenica).

Vasculite

© James Heilman, MD, CC BY-SA 3.0, via Wikimedia Commons

Nodules

• Common causes of a nodule include a cisti sebacea, lipoma, cancro della pelle, or a wart.

• Other causes include rheumatoid nodules (associated with artrite reumatoide) and Heberden's nodes (associated with osteoartrite).

Blisters

• Skin inflammation, including reactions to medicines, dermatite da contatto, eczema. Eczema on your legs may be caused by varicose veins (eczema varicoso).

• Diseases of your immune system - eg, bullous pemphigoid.

• Viral infections - eg, varicella, malattia mani-piedi-bocca.

• Skin infection: a germ (bacterial) infection with impetigine or viral infection with herpes simplex (herpes labiale oppure herpes genitale) or with herpes zoster (shingles).

• Rarer causes include pemfigo e pemfigoide.

Pustules

• Skin infection by a virus (eg, herpes labiale due to herpes simplex virus) or bacterial germs (impetigine).

• Inflammation - eg psoriasi.

• Pustular skin reaction to medicine you are taking.

• Pustules on your face may be acne or rosacea.

Ulcere

Ulcers may be due to venous leg ulcers, ulcere da pressione, diabetes skin ulcers oppure cancerous (malignant) skin ulcers.

This leaflet is a guide but if you have any concerns, you must telephone or see your GP, especially if:

• The rash doesn't quickly disappear.

• You feel unwell.

• The rash does not fade with pressure (the best way to test this is to press a glass gently against the rash to see if it fades).

• You are not sure what has caused the rash or have any other concerns.