A dermatology referral is not one threshold but three, separated by how fast the appointment needs to happen. NICE's guideline for children under 12 sets them out: same day if eczema herpeticum is suspected, within two weeks for severe eczema that has not responded to optimal topical therapy after a week, and routine for eczema that is simply not being controlled. The criteria quoted below are written for children. The NHS patient page says only that a GP can prescribe some treatments, "or you may be referred to a skin specialist (dermatologist)".
Same day: suspected eczema herpeticum
The guideline names exactly one same-day category: "Immediately (same day) refer children for specialist dermatological advice if eczema herpeticum is suspected" (NICE CG57, 1.7.1.1). Eczema herpeticum is herpes simplex virus spreading through skin whose barrier is already broken, which is why a familiar patch can start behaving differently within a day or two.
The NHS lists the signs that warrant an urgent GP appointment or a call to NHS 111: eczema that is "blistered, crusty, leaking fluid or has spots filled with pus", "painful, swollen or feels warm", or "suddenly gets worse or gets bigger", and a high temperature or feeling generally unwell (NHS, Atopic eczema). Those signs cover bacterial infection as well, and the two are not reliably told apart by looking, so the urgency is the same either way.
Within two weeks: severe eczema that has not responded, or infection that has not cleared
Two situations get the urgent route: "their atopic eczema is severe and has not responded to optimal topical therapy after 1 week", and "treatment of bacterially infected atopic eczema has failed" (NICE CG57, 1.7.1.2). The first clause carries a condition that is easy to skim past. The therapy has to have been optimal: the right potency for the site, applied to all the affected skin, over emollient, for the full week.
A fortnight of occasional mild steroid cream on severe eczema is not a failed treatment. It is an untested one, and a referral on that basis tends to return you to the same steps in a hospital clinic months later, so it is worth being able to say what was applied, where, how often and for how long. The guideline's own sequence at 7 to 14 days is to exclude secondary bacterial or viral infection, step up potency, and then, "if the atopic eczema is still uncontrolled, review the diagnosis and refer" (NICE CG57, 1.5.1.16).
The routine referral list, in the guideline's own words
The routine list is longer than most people expect. Recommendation 1.7.1.3 refers children when:
- "the diagnosis is, or has become, uncertain"
- "management has not controlled the atopic eczema satisfactorily", on "a subjective assessment by the child, parent or carer", for example "1 to 2 weeks of flares per month" or "adverse reactions to many emollients"
- "atopic eczema on the face has not responded to treatment"
- the family may benefit from "specialist advice on how to apply treatments (for example, bandaging techniques)"
- "contact allergic dermatitis is suspected", for instance in "facial, eyelid or hand atopic eczema"
- the eczema "is causing significant social or psychological problems", such as "sleep disturbance or poor school attendance"
- it "is associated with severe and recurrent infections, especially deep abscesses or pneumonia"
The control threshold repays a second reading. It is subjective, set by the patient or carer rather than a clinician's view of the skin, and one to two weeks of flares a month is a low bar. Suspected food allergy sits under its own recommendation for specialist investigation, not on this list, and the conditions that trigger it in a child are set out in baby eczema and food allergy.
How the referral works, and what the wait is
Referrals start at the GP and go through the NHS e-Referral Service. The national standard is that "the maximum waiting time for non-urgent, consultant-led treatments is 18 weeks", counted from the day the appointment is booked or the referral letter arrives (NHS, Guide to NHS waiting times in England). That is a standard, not a description of the dermatology wait in any particular area. The referral route itself, and the UK organisations that sit alongside it, are set out in eczema support in the UK.
What you bring to the GP appointment matters, because most criteria above turn on history rather than appearance. A trigger log with dated severity scores answers the flare-frequency question, and photographs from a flare answer what an appointment on a good skin day cannot.
What a dermatology appointment involves
Expect severity to be scored rather than described. NICE asks for a holistic assessment at each consultation, covering severity and "quality of life, including everyday activities, sleep, and psychosocial wellbeing", and notes that "there is not necessarily a direct relationship" between the two. It names the Patient-Oriented Eczema Measure for severity and the Children's Dermatology Life Quality Index for quality of life.
POEM is seven questions about the past week, banded 0 to 2 for clear or almost clear, 3 to 7 mild, 8 to 16 moderate, 17 to 24 severe and 25 to 28 very severe (Charman et al, 2013). Clinics and trials also use the Eczema Area and Severity Index, which rates four signs (redness, thickness, scratching and lichenification) across four body regions, with a maximum of 72 (DermNet).
Patch testing is the second thing a clinic can do that primary care cannot: "a specialist procedure carried out in dermatology departments" testing for "an allergy to substances which have come into contact with your skin", run over "3 appointments during a one-week period" against the 50 or so commonest contact allergens. It "will not detect food allergies" (British Association of Dermatologists).
Third is treatment above what primary care prescribes: phototherapy, systemic immunosuppressants, and the biologics and JAK inhibitors licensed for moderate to severe atopic dermatitis. Which of those a clinic can offer you, and in what order, follows the NICE appraisal covering each drug.
What to do between the referral and the appointment
An 18-week standard means the self-managed side carries on regardless. The NHS floor for emollients is "as often as possible (at least 2 times a day)", and that is the layer everything else sits on.
For a severe flare during the wait, wet wrap therapy is the step between ordinary emollient use and a hospital appointment, and bandaging technique is one of the things the guideline expects a specialist to teach.
If prescribed treatment has been used properly and the eczema is still not settling, a structured 45-day protocol covers ground a ten-minute appointment does not: environmental audit, trigger identification, dietary investigation and barrier repair, reassessed at day 30 and day 45. It runs alongside medical care, and its log is the most useful thing you can hand a dermatologist.
References
- National Institute for Health and Care Excellence. Atopic eczema in under 12s: diagnosis and management (CG57), 2025. https://www.ncbi.nlm.nih.gov/books/NBK571009/
- NHS. Atopic eczema. https://www.nhs.uk/conditions/atopic-eczema/
- NHS. Guide to NHS waiting times in England. https://www.nhs.uk/nhs-services/hospitals/guide-to-nhs-waiting-times-in-england/
- British Association of Dermatologists. Patch testing, patient information, 2024. https://www.skinhealthinfo.org.uk/condition/patch-testing/
- Charman CR, Venn AJ, Ravenscroft JC, Williams HC. Translating Patient-Oriented Eczema Measure (POEM) scores into clinical practice by suggesting severity strata derived using anchor-based methods. British Journal of Dermatology, 2013. https://pmc.ncbi.nlm.nih.gov/articles/PMC3920642/
- DermNet. EASI score. https://dermnetnz.org/topics/easi-score