Rashes Flashcards
Erythema Multiforme
Erythema multiforme is a hypersensitivity reaction that is most commonly triggered by infections. It may be divided into minor and major forms. immune-mediated, typically self-limiting mucocutaneous condition characterised by ‘target’ lesions
Previously it was thought that Stevens-Johnson syndrome (SJS) was a severe form of erythema multiforme. They are now however considered as separate entities.
Features
target lesions: A central, dusky area of epidermal necrosis, Surrounded by a lighter oedematous area With a peripheral erythematous margin.
initially seen on the back of the hands / feet before spreading to the torso (peripheral to central)
upper limbs are more commonly affected than the lower limbs, extensor surface
pruritus is occasionally seen and is usually mild
Significant mucosal involvement distinguishes erythema multiforme major from multiforme minor
Causes
viruses: herpes simplex virus (the most common cause), Orf*
idiopathic
bacteria: Mycoplasma, Streptococcus
drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
connective tissue disease e.g. Systemic lupus erythematosus
sarcoidosis
malignancy
-Management:
=Avoid ocular involvement (keratitis, scarring, uveitis)
=Itch — oral antihistamines and/or topical steroids for itch or discomfort associated with cutaneous lesions
Pain — for mild mucosal involvement, oral washes containing antiseptic or local anaesthetic.
=Prednisolone for severe mucosal disease
Antiviral for recurrent disease
Erythema nodosum
Overview
inflammation of subcutaneous fat
typically causes tender, erythematous, nodular lesions
usually occurs over anterior shins, may also occur elsewhere (e.g. forearms, thighs)
usually resolves within 6 weeks, commonly young (25-40), more common in women post puberty
lesions heal without scarring
=tender bilateral erythematous subcutaneous nodules 3–20 cm in diameter erupting over one to several weeks. They are accompanied by fever and joint pain. In 50% the ankle is swollen and painful for up to several weeks. The knees and other joints can also be affected
Causes
infection
=streptococci
=tuberculosis
=brucellosis
systemic disease
=sarcoidosis
=inflammatory bowel disease
=Behcet’s
malignancy/lymphoma
drugs
=penicillins
=sulphonamides
=combined oral contraceptive pill
pregnancy
Investigations
-Complete blood count with differential, C-reactive protein levels (infectious and inflammatory causes)
Chest X-ray (tuberculosis and sarcoidosis)
Throat swab and anti-streptolysin O and streptodornase serology (streptococcal infection)
Viral serology (preferably two samples at four-week intervals)
Stool culture and evaluation for ova and parasites in patients with gastrointestinal symptoms
Mantoux test or QuantiFERON gold (tests for TB).
Deep incisional or excisional skin biopsy.
Management:
-Pain management may include extended rest, colchicine (1–2 mg/day), NSAIDs (non-steroidal anti-inflammatory drugs), and venous compression therapy [4].
Systemic corticosteroids (1 mg/kg daily until resolution of erythema nodosum) may be prescribed if infection, sepsis
, and malignancy have been ruled out [9,11].
Oral potassium iodide as a supersaturated solution (400–900 mg/day) may be prescribed for one month if available
Guttate psoriasis
Guttate psoriasis is more common in children and adolescents. It may be precipitated by a streptococcal infection 2-4 weeks prior to the lesions appearing, particularly tonsillitis
Features
tear drop papules on the trunk and limbs, acute onset over days
=gutta is Latin for drop
=pink, scaly patches or plques of psoriasis
tends to be acute onset over days
=Small, scattered, round or oval (2 mm to 1 cm in diameter - water drop appearance) scaly papules, which may be pink or red.
Multiple lesions which may occur all over the body over a period of 1–7 days, particularly on the trunk and proximal limbs. Lesions may occur on the face, ears, and scalp, but rarely affect the soles of the feet.
Guttate psoriasis mostly occurs in children, teenagers and young adults, although it can also occur in older adults.
A first presentation of psoriasis (classically after acute streptococcal upper respiratory tract infection), or as an acute exacerbation of plaque psoriasis.
Investigation:
-Wabs for bacteria
-ASOT blood titre
Management
-most cases resolve spontaneously within 2-3 months/ 3-4, not infectious
-there is no firm evidence to support the use of antibiotics to eradicate streptococcal infection
-topical agents as per psoriasis (corticosteroids, emollient, vit D prep)
-UVB phototherapy: urgent referral to derm when lesions widespread (>10%)
-tonsillectomy may be necessary with recurrent episodes
-Assess for stress, distress, anxiety, depression
-25% develop chronic plaque psoriasis
Assessment of guttate psoriasis
The sites and extent of involvement, to help classify the type of psoriasis, which will guide management.
Symptoms of skin involvement, such as itch, irritation, burning, pain, bleeding, and scaling.
Periods of symptom flares and remission, as psoriasis typically has a chronic relapsing-remitting course.
Symptoms of systemic illness, such as fever, malaise, and weight loss, especially if medical emergencies such as generalized pustular psoriasis or erythrodermic psoriasis are suspected.
Any known trigger factors or any relationship to areas of trauma, suggesting the Koebner phenomenon.
Articular symptoms of unexplained joint stiffness, pain, or swelling; or nail changes, that may suggest a diagnosis of psoriatic arthritis.
Consider using the Psoriasis Epidemiology Screening Tool (PEST) — if a person scores three or more out of five, consider arranging a referral to a rheumatologist.
Note: the PEST does not detect axial arthritis or inflammatory back pain.
Associated conditions such as inflammatory bowel disease or obesity.
Any treatments used, including over-the-counter preparations.
The person’s perception of the severity of psoriasis — consider using the 6-point Patient’s Global Assessment (PGA) score with points indicating increasing severity: ranging from clear (scores 0); nearly clear; mild; moderate; severe; or very severe (5).
The physical, psychological, and social impact of psoriasis on the person’s daily functioning and activities, including home, work, leisure, and/or impact on family or other dependents.
Consider using a validated quality of life assessment tool, such as the Dermatology Life Quality Index (DLQI) tool or the Children’s Dermatology Life Quality Index (CDLQI) for assessing the impact of psoriasis in adults and children.
Be aware that the degree of impact may not correlate with objective measures of disease extent or severity.
Any associated stress, distress, anxiety and/or depression.
Any family history of psoriasis or psoriatic arthritis.
If any therapies have been attempted, and how effective they have been.
Assess the person’s:
Cardiovascular risk
Examine the person:
Assess for signs of systemic illness, such as fever or hypothermia, weight loss, dehydration, tachycardia, hypotension (may be seen in generalized pustular psoriasis or erythrodermic psoriasis).
Assess skin lesions over the whole body, where possible, to classify the type of psoriasis by considering:
Distribution — psoriasis often occurs on extensor surfaces (elbows and knees), trunk, flexures, sacral and natal cleft, scalp and behind the ears, and umbilicus.
Size and shape of lesions — plaque psoriasis generally presents as large plaques, whereas guttate psoriasis presents as smaller ‘droplet’ lesions. There is usually a clear delineation between normal and affected skin.
Number of lesions — some people will have only a few lesions (for example chronic plaque psoriasis affecting only the extensor surfaces), but others will have many (for example, numerous small lesions of guttate psoriasis).
Severity of lesions — consider recording the severity of psoriasis using the 6-point Static Physician’s Global Assessment (PGA) score with points indicating increasing severity: ranging from clear (scores 0); nearly clear; mild; moderate; severe; or very severe (5). Note: be aware that erythema may be under-estimated in people with pigmented skin types.
Surface features — whether smooth, scaly, or pustular.
Colour — may be pink or red, but in people with pigmented skin, this may not be obvious. Scale is typically silvery in colour.
Auspitz sign — the observation of pinpoint bleeding when adherent psoriatic scales are scraped away.
Involvement of other areas — such as signs of joint tenderness or swelling suggesting psoriatic arthritis, or nail changes.
Assess and document the proportion of total body surface area (BSA) affected by psoriasis, which can be estimated using the ‘Rule of Nines’ (traditionally used for burns assessment). Estimates of body surface area:
Arm — 9%.
Head — 9%.
Neck — 1%.
Leg — 18%.
Anterior trunk — 18%.
Posterior trunk — 18%
Pityriasis rosea
Pityriasis rosea describes an acute, self-limiting rash which tends to affect young adults. The aetiology is not fully understood but is thought that herpes hominis virus 7 (HHV-7) may play a role.
Features
=in the majority of patients there is no prodrome, but a minority may give a history of a recent viral infection
=herald patch (usually on trunk) before generalised eruption (5-15 days)
=followed by erythematous, oval or circular, scaly patches which follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer.
=Multiple discrete salmon coloured or fawn coloured, flat or slightly raised, typically 0.5-1cm
=the centre tends to clear leaving the classical appearance of peripheral ‘collarette’ scaling around the edge of the lesion.
=This may produce a ‘fir-tree’ appearance
=The lesions are not vesicular and do not tend to occur on palmar or plantar skin surfaces.
=The rash is usually symmetrical.
=Most lesions occur on the trunk and proximal limbs, with few (usually less than 10%) distal to the mid-upper arm and mid-thigh.
=On the trunk, lesions occur along the lines of cleavage parallel to the ribs (forming a ‘Christmas tree’ pattern on the upper back and V-shaped pattern on the upper chest) and are distributed transversely across the lower abdomen and lower back.
=The face and scalp may be involved in children.
-Management
self-limiting - usually disappears after 6-12 weeks, not usually recurring/ some pigmentation, symptomatic itch (emollient, corticosteroid, antihistamine)
-Consider whether rash may be caused by HIV or syphilis. Reconsider diagnosis if rash >12 weeks
-Urgent secondary care in pregnancy
Clinical criteria for pityriasis rosea
-Discrete circular or oval lesions
-Scaling on most lesions
-Peripheral collarette scaling with central clearance on at least two lesions
-Optional (At least one of the following features)
=Truncal and proximal limb distribution ( 10% of lesions distal to mid-upper-arm and mid-thigh)
=Most lesions along skin cleavage lines
=Herald patch ≥ 2 days before other lesions
-Exclusion
=Multiple small vesicles at the centre of ≥ 2 lesions
=≥ 2 lesions on palmar or plantar skin surfaces
Differentials of pityriasis rosea
-Guttate psoriasis
-Discoid/ nummular eczema: very itchy coin shaped plaques, may be vesicular or crusted, limbs and lesser extent trunk
-Drug reactions
-HIV seroconversion: symmetrical, erythematous, maculopapular, affects palms and soles and face as well
-Lichen planus: itchy, shiny, violaceous, flat-topped, polygonal papules on flexor surface, fine white lines on buccal mucosa
-Pityriasis lichenoides: chronic form small firm scaly papules
-Pityriasis versicolor: round/oval macules with fine scaly edge
-Polymorphic eruption of pregnancy: discrete itchy papules and plaques on abdo
-Annular legions
Acute rashes in GP
-Erythema multiforme
-Erythema nodosum
-Guttate psoriasis
-Pityriasis rosea
Differentiating guttate psoriasis and pityriasis rosea
Prodrome:
-GP: Classically preceded by a streptococcal sore throat 2-4 weeks
-PR: Many patients report recent respiratory tract infections but this is not common in questions
Appearance
-GP: ‘Tear drop’, scaly papules on the trunk and limbs
-PR: Herald patch followed 1-2 weeks later by multiple erythematous, slightly raised oval lesions with a fine scale confined to the outer aspects of the lesions. May follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer. This may produce a ‘fir-tree’ appearance
Treatment/ natural history
-GP: Most cases resolve spontaneously within 2-3 months. Topical agents as per psoriasis
UVB phototherapy
-PR: Self-limiting, resolves after around 6 weeks
