Dermatological Diagnoses Not To Be Missed

Melanoma is a pigmented lesion that has changed in size, shape or colour, and may be scaly, itchy or bleeding.

This is unlikely to be the reason for presentation to the ED but may be an incidental finding during examination and should not be ignored.

30% develop in pre-existing moles, the rest on previously unblemished skin. There are approximately 1000 deaths per year [4].

Image reproduced from the US Federal Government via Wikimedia.

Toxic epidermal necrolysis

Erythema multiforme, Steven-Johnson syndrome and Toxic epidermal necrolysis (TEN) are a spectrum of the same disease.

They often start with prodromal symptoms such as more throat, myalgia and malaise which is followed by a macular rash with the appearance of target lesions.

Steven-Johnson syndrome is erythema multiforme with involvement of the oral, conjunctival and/ or genital mucosa. Steven-Johnson’s usually affects less than 10% of total body surface are whilst TEN is typically greater than 30%. In both these diseases Nikolsky’s sign is positive (skin is removed by shearing force).

TEN can be caused by meds (eg. sulphonamides, beta-lactams, anticonvulsants etc), infection or malignancy however it is idiopathic in up to 50% of cases.

The mortality rate of TEN can be as high as 30%.

Image reproduced with permission from CDC.

Scalded skin syndrome 

This is a desquamating skin disorder caused by the toxins produced by Staph. Aureus.

A young child (<6) typically presents with fever, irritability and a tender red rash. Initially this rash is erythematous but then becomes bullous before exfoliating. Nikolsky sign is positive. Severity can range from a couple of blisters to exfoliation of most of the body.

This exfoliation leaves the skin predisposed to secondary infections. Mortality is 1- 5%

In scalded skin syndrome, mucous membranes are spared which helps us differentiate clinically between this and Steven-Johnson’s or TEN.

Image reproduced with permission of CDC/Allen W. Mathies, MD.

Erythroderma

Erythroderma is scaling erythematous dermatitis involving >90% of body surface. There are many causes, for example eczema, psoriasis, drug eruptions or lymphoma. It is most common in middle-aged and elderly men and it can spread from a small scaly patch to covering the whole body in as little as 12 hours.

The rash is warm and usually accompanied by a problematic itch which can be intolerable.

The condition is associated with several serious systemic features such as cardiac failure, hypothermia and dehydration [6].

Image reproduced with permission from CDC.

Necrotising fasciitis

Necrotising fasciitis is an insidiously-advancing soft tissue infection, extending into the fascia and underlying muscle. It will progress rapidly causing massive tissue destruction and despite aggressive treatment can be fatal. Mortality is around 20%.

Most cases are polymicrobial. Of the cases caused by a single organism, group A Strep is the most common.

Initially there may be cellulitc changes, limb oedema or a small wound infection. The skin appearances will progress rapidly. There may also be crepitus, sloughing and blistering. The patient may become systemically unwell and develop septic shock.

The best sign pointing to this diagnosis is intense pain which is out of proportion to the physical appearance.

Urgent surgical debridement and broad spectrum antibiotics such as clindamycin are required.

Because of the severity and rapid progression of necrotising fasciitis, it should always be considered in any patient who has a skin or soft tissue infection with systemic toxicity or severe pain.

Image reproduced with permission of CDC/M. A. Parsons/Donated by Dr. G. Rosenfeld – Head Hospital Vital, of Dept. of Physiopathology, Brazil.

Meningococcal septicaemia

Classic haemorrhage lesions of petechia and purpura (as seen in the picture) are present in up to 77% of patients with meningococcal septicaemia and also more than 50% of patients with meningococcal meningitis.

It is caused by Neisseria meningitidis infection. There are more than 13 subgroups but A, B, C, Y and W-135 cause the most amount of infections.

Septicaemia without meningitis carries a higher mortality than meningitis alone.

Presentation can range from mild febrile illness to a fulminant disease progressing to death within hours.

If meningococcal disease is expected then blood tests should include FBC, CRP, coag, blood cultures, PCR for N. meningitidis, BM and VBG.

Patients should be treated immediately if they have a spreading petechial rash; signs of bacterial meningitis; signs of septicaemia or they appear ill.

Children under 3 months should be treated with IV cefotaxime and amoxicillin/ ampicillin. Children over 3 months and adults should be treated with IV ceftriaxone.

Image reproduced with permission from CDC/Mr Gust.

Lyme disease