Most dermatology is not urgent, and the selection panels test the part that is. A junior dermatology registrar must recognise the rash that is an emergency, act on it, and know when the patient belongs in a ward rather than a clinic. This guide covers the emergencies that recur in selection scenarios and the structure that scores.
The structure
Recognise the emergency and name the diagnoses that must not be missed. Assess: the history including every drug and its timing, the extent of skin involvement, the mucosal surfaces, the systemic features. Treat what must be treated now and stop what must be stopped. Admit and involve the right teams. Explain to the patient. Say what you would do if the first step failed.
The severe cutaneous adverse reaction
A patient presents with a rapidly spreading blistering rash, mouth ulcers and fever after starting a new drug. The diagnoses: Stevens Johnson syndrome and toxic epidermal necrolysis, with drug reaction with eosinophilia and systemic symptoms in the differential. The assessment: the drug history with the timing, the body surface area involved, the mucosal involvement, the skin tenderness, the systemic features, the bloods. The actions: stop the suspected drug and every non essential drug, admit, the supportive care that a large burn needs (fluids, temperature, pain, wound care, infection surveillance), the ophthalmology review for the eyes, the dermatology consultant now, and the burns or intensive care unit for extensive involvement. The severity score. Say that you would not wait for a biopsy to act. Then the aftermath: the reaction documented and reported, the patient told the drug and its class must never be taken again, and the allergy recorded.
Erythroderma
A patient with psoriasis has become erythrodermic. The skin has failed as an organ: fluid loss, temperature instability, protein loss, high output cardiac strain, and the risk of sepsis. The assessment: the cause (the psoriasis itself, a drug, a withdrawn treatment, a second diagnosis such as lymphoma), the observations, the fluid status, the bloods. The actions: admit, fluids and temperature control, emollients and the appropriate topical treatment, treat the cause, watch for infection, and the consultant involved for the systemic treatment decision. Say what you would stop: the drug that may have triggered it, and any systemic steroid that may have been withdrawn abruptly.
The infection in the immunosuppressed patient
A patient on a biologic for psoriasis develops a cough and night sweats. The diagnoses that must not be missed: tuberculosis reactivated, other opportunistic infections, lymphoma. The actions: the biologic withheld, the investigations including imaging and the tests for tuberculosis, the respiratory or infectious diseases involvement, and the dermatology consultant told. Say that the screening before the biologic was started would be reviewed, and that the patient's psoriasis would be managed in the meantime.
The changing pigmented lesion
Not an emergency in hours but an emergency in weeks. The assessment: the history of change, the features, dermoscopy, and the decision to excise. The actions: excision biopsy with the margins the guidelines set, the histology, the staging if melanoma, the multidisciplinary pathway, and the conversation with the patient. Say that you would not shave or sample a suspected melanoma.
The febrile child with a widespread rash
The differentials that must not be missed: meningococcal disease, staphylococcal scalded skin syndrome, Kawasaki disease, the drug reactions, the viral exanthems that are serious in the immunocompromised. The assessment of the child as a child: the observations, the capillary refill, the mucosa, the lymph nodes. The actions depend on the diagnosis, and the paediatric team is involved early.
Necrotising soft tissue infection
Sometimes added: the rapidly spreading painful cellulitis with pain out of proportion and systemic toxicity. Recognise it, the surgical team immediately, antibiotics, and no delay for imaging.
What the panels score
Recognition, the drug history taken properly, the skin treated as an organ that can fail, early admission and the right teams, the patient told honestly, and the aftermath including the allergy recorded. The common failures are managing a severe cutaneous reaction as an outpatient, missing the eyes, and continuing the drug.
Preparing
Learn the hospital's pathways for each emergency. Talk each scenario through aloud in two minutes with the worsening prepared. The emergencies are a small part of dermatology and a large part of its selection, because they are where a registrar's judgement matters most.