Author: Alexandra Newman / Editor: Adrian Boyle / Reviewer: Raghaventhar Manikandan / Code: DC10, DC2, DC4, DC5, DC6, DC9, DP1, DP2, NeuC6, SLO1, SLO3, SLO5Published: 11/07/2023



The skin is the largest organ in the body. In an adult it can cover an area of 2 square metres and present a multitude of clinical signs and symptoms.

For example, a rash is a common presentation to the emergency department (ED) and may be a sign of serious illness or systemic disease. Signs and symptoms can therefore be purely dermatological, or a manifestation of a systemic condition.

Dermatology can appear daunting because of the large number of different terms used to describe clinical findings, and because of clinical findings being the main part of the diagnostic process without further investigations.

There are also several rare, life-threatening conditions that may be missed by the emergency physician who is not familiar with them.

History and Key Factors

As with other systems, making a dermatological diagnosis consists of taking a history, examining the patient and performing appropriate investigations.

In the history there are a few salient points to consider when evaluating a patient with a skin condition1,3. These are:

Presenting a complaint
  • When, where and how problems started
  • Symptoms, e.g. itching
  • Aggravating factors, e.g. sunlight
Past history
  • Systemic illness, e.g. diabetes/TB/cancer
  • Previous skin problems
  • Atopic conditions, e.g. hayfever/asthma
  • Allergies (not just to medications)
  • Prescribed and over the counter medications
Family history
  • Infectious contacts
  • Genetic conditions
  • Sexual contacts
  • Chemicals or materials the patient may have come into contact with
  • Animals or pets
  • Living conditions
  • Alcohol intake
  • Travel history to endemic areas / trekking history to tick prone areas

The patient should be inspected from head to toe including the nails, mouth and scalp. Examination should include patient’s temperature along with all other vital signs, and examination of other relevant organ systems. After a full inspection, any lesions found should be palpated and measured2.

A structured method for assessing lesions is illustrated on the body map below1,3


Having completed the history and examination, it is important to be able to describe the findings using the correct terminology.

MACULE: A flat circumscribed area of discoloured skin (CDC)


PAPULE: Circumscribed skin elevation <0.5 cm (CDC/Dr Robinson)


NODULE: Circumscribed lump >0.5 cm (CDC/Dr Steve Kraus)


PLAQUE: Circumscribed disc-shaped elevation: <2 cm = small, >2 cm = large (CDC/Gavin Hart)


VESICLE: Visible collection of fluid <0.5 cm (CDC/Dr Noble)


BULLA: Visible collection of fluid >0.5 cm (CDC/Dr John Noble Jr)


PUSTULE: Visible accumulation of pus (CDC/Brian Hill)


ULCER: Loss of epidermis (CDC/Dr Sellers)


WHEAL: Circumscribed area of cutaneous oedema (CDC/Dr William Foege)


There are many other terms used in dermatology. Some of these other terms will be useful in emergency medicine.

ABSCESS: Localised collection of pus (CDC/Bruno Coignard and Jeff Hageman)


ANNULAR: Ring-shaped (CDC/Renelle Woodall)


BURROW: Tunnel in the skin caused by a parasite e.g. scabies (CDC)


CARBUNCLE: Collection of furuncles (Wikimedia/Drvgaikwad)


CRUST: Dried exudate (CDC/Dr. Dancewiez)


CYST: Epithelial lined cavity filled with fluid or semi-solid matter (Wikimedia/Steven Fruitsmaak)


ERYTHEMA: Redness of the skin caused by vascular dilatation  (CDC/M.A.Parsons)


EXCORIATION: Superficial abrasion due to scratching (Wikimedia/Berteun)


FOLLICULITIS: Inflammation of hair follicles (Wikimedia)


FURUNCLE: Pyogenic infection of the hair follicles (Wikimedia/Mahdouch)


LICHENIFICATION: Chronic thickening of the skin caused by rubbing or scratching (CDC)


PETECHIA: Haemorrhagic spot 1-2 mm diameter (CDC)


PURPURA: Extravasation of blood causing red discolouration of the skin or mucous membranes (CDC)


Telangiectasia: Dilated dermal blood vessels causing visible lesion (CDC/Robert E. Sumpter)


There are several serious conditions in dermatology that need to be immediately recognised. Fortunately for patients they are all relatively uncommon, however this may mean that you have never seen them before and might not immediately consider them as a diagnosis. This makes it even more vital that there is awareness in the ED of these medical emergencies.


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 (e.g. 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 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
Lyme disease is a cutaneous and systemic infection with Borrelia burgdorferi (a spirochaete spread by tick-bite). It is characterised by a slowly expanding erythematous ring from the site of the tick bite; this is called erythema chronicum migrans and it occurs in 80% of cases.
Lyme disease tends to be treated with a prolonged course of doxycycline.

Systemic features include:

  • Arthritis
  • Myalgia
  • Palpitations
  • Bell’s palsy
  • Meningitis
  • Polyneuropathy
  • Psychosis

Image reproduced with permission from CDC/James Gethany.

  1. Graham-Brown R, Burns T. Lecture Notes: Dermatology. 8th edn. Blackwell Publishing, 2002: 9-12.
  2. Marks JG Jr, Miller JJ. Principles of Dermatology. 4th edn. Saunders Elsevier, 2006: 15-33.
  3. Gawkrodger DJ. Dermatology: An Illustrated Colour Text. 3rd edn. Churchill Livingstone, 2002: 14-19.
  4. Collier J, Longmore M, Duncan-Brown T. Oxford Handbook of Clinical Specialties. 5th edn. Oxford: Oxford University Press, 1999: 576-593.
  5. Gawkrodger DJ. Dermatology: An Illustrated Colour Text. 3rd edn. Churchill Livingstone, 2002: 45.
  6. Graham-Brown R, Bourke J, Cunliffe T. Dermatology Fundamentals of Practice. Mosby Elsevier, 2008: 208-209.
  7. National Institute for Health and Care Excellence (NICE). Meningitis (bacterial) and meningococcal septicaemia in under 16s: recognition, diagnosis and management. Clinical guideline [CG102], 2010. Last updated: 01 February 2015. [Accessed June 2023].
  8. Walls, Hockberger and Gausche-Hill. Rosen’s Emergency Medicine Concepts and Clinical Practice. 9th edn. Elsevier, 2017.

We should like to thank the following for permission to reproduce images:

  • Centre for Disease Control
  • Wellcome Images