{'fraction_non_alphanumeric': 0.01861547411285631, 'fraction_numerical': 0.009889470622454915, 'mean_word_length': 5.440074906367041, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Towards a diagnosis of cellulitis

Accurate diagnosis is important for patient management, ensuring patients get the right treatment for their condition and are not exposed to unnecessary or potentially harmful interventions. Cellulitis is a common condition, responsible for 14 5 million cases, 2 9 million emergency department visits and over 650 000 admissions annually in the U.S.A., and 88 664 hospital admissions in England in 2017–18. As well as the morbidity, the economic burden is considerable, amounting to $13 7 billion for emergency department and inpatient care in the U.S.A. with the cost to the NHS averaging £122 million pounds annually for nonelective admissions for cellulitis. Patients may present to primary or secondary care and be managed by clinicians from different specialties. Diagnosis is clinical, however, despite the frequency of this condition and the availability of management guidelines detailing clinical features and differential diagnoses, it is surprising that onethird of patients initially diagnosed with cellulitis are subsequently found to have another condition. The most common site of cellulitis is the lower limb and the differential diagnosis of conditions with similar clinical features is wide. As the diagnosis depends on clinical evaluation, it is perhaps unsurprising to learn that dermatologists are considered best at diagnosing cellulitis. This may be because they are likely to have greater knowledge and experience of the differential diagnoses. Further adding to the diagnostic confusion, many of these other conditions, such as eczema and lymphoedema may both coexist with, and predispose to, cellulitis. Despite the prevalence, clinical importance and economic burden of cellulitis, there are no published formally validated diagnostic criteria. In addition to optimizing patient management, accurate diagnostic criteria are also essential for research purposes. The importance of accurate diagnosis and clear diagnostic criteria for cellulitis was highlighted in the 2017 Priority Setting Partnership. In this issue of the BJD, Patel et al. report the results of a systematic review to identify and describe diagnostic criteria and tools that have been developed for lower-limb cellulitis. As cellulitis and erysipelas are often clinically indistinguishable and the conditions may overlap, studies of both conditions were included. The authors provide a narrative synthesis and assessment of the methodological quality of eight small studies of patients with lower-limb cellulitis that included diagnostic criteria or tools for diagnosis. Most were case–control studies, with one cohort study and one cross-sectional study. The studies mostly compared cellulitis to another diagnosis, for example, deep vein thrombosis, osteomyelitis or gout and sought to identify differences in clinical or laboratory features. In one study, Raff et al. describe a simple scoring system, the ALT-70, to differentiate cellulitis from other conditions. This review highlights the paucity of literature on properly validated diagnostic criteria for cellulitis. Although assessment by a trained dermatologist is the current gold standard for diagnosis, it is likely that most patients will not have immediate access to a dermatological opinion. The challenge now remains to develop a diagnostic tool that can be easily applied by the assessing clinician irrespective of the setting or specialty.