Skin nodules are larger than papules – more than 5mm diameter. However, their depth is more significant clinically than their width. Some are free within the dermis; others are fixed to skin above or subcutaneous tissue below. The causes are various; the patient is usually concerned about the cosmetic appearance or malignant potential.

Published: 2nd August 2022 | Updated: 15th August 2022

Differential diagnosis

Common Diagnoses

  • Sebaceous Cyst
  • Lipoma
  • Basal Cell Carcinoma (BCC)
  • Warts
  • Xanthoma

Occasional Diagnoses

  • Dermatofibroma (Histiocytoma)
  • Squamous Cell Carcinoma
  • Nodulocystic Acne
  • Kerato-Acanthoma
  • Gouty Tophi
  • Chondrodermatitis Nodularis Chronica Helicis
  • Rheumatoid Nodules and Heberden’s Nodes
  • Pyogenic Granuloma

Rare Diagnoses

  • Malignant Melanoma (becoming more common in the UK)
  • Vasculitic: Erythema Nodosum, Nodular Vasculitis, Polyarteritis Nodosa
  • Atypical Infections (e.g. Leprosy, Treponema, Lupus Vulgaris, Fish Tank and Swimming Pool Granuloma, Actinomycosis)
  • Lymphoma and Metastatic Secondary Carcinoma
  • Sarcoidosis
  • Pretibial Myxoedema

Ready reckoner

Key distinguishing features of the most common diagnoses

XanthomaSebaceous CystBCCWartLipoma
Central PunctumNoYesNoNoNo
Characteristic DistributionYesNoYesNoNo
Normal Skin SurfaceNoYesNoNoYes

Possible investigations

Likely: None (skin biopsy or cytology if doubt about the lesion or clinical diagnosis of possible carcinoma).

Possible: Lipid profile, FBC, ESR/CRP, urate, rheumatoid factor/anti-CCP, urinalysis.

Small Print: TFT, skin biopsy, further investigations guided by clinical picture (see below).

  • Excision biopsy is the definitive investigation for achieving a diagnosis; cytology from skin scrapings can be used to diagnose BCC.
  • Lipid profile: Xanthomata require a full lipid profile to define any underlying hyperlipidaemia.
  • Urinalysis: If suspect inflammatory or vasculitic skin lumps, as may reveal proteinuria if associated with systemic and renal disorders.
  • FBC and ESR/CRP: ESR/CRP raised in inflammatory disorders and malignancy; may also reveal anaemia of chronic disease or malignancy (including lymphoma).
  • Check urate if gouty tophi are clinically likely.
  • Rheumatoid factor/anti-CCP: Nodules are usually associated with positive rheumatoid factor.
  • TFT: To diagnose Graves’s disease with pretibial myxoedema.
  • Skin biopsy: May contribute to a diagnosis of sarcoidosis
  • Further investigations according to clinical picture: Some lesions, such as erythema nodosum, may require further investigation to establish the underlying cause; histological confirmation of skin secondaries may similarly require further assessment, although the overall condition of the patient may mean this is a futile exercise.

Top Tips

  • Look at the lesion under the magnifying glass – this may reveal suspicious signs such as ulceration or a rolled, pearly edge.
  • In uncertain cases which do not require urgent attention, record your findings carefully (including precise dimensions) and review in a month or two.
  • Stoical patients may underestimate the significance of a suspicious lesion, particularly if you discover it during a routine examination – if you are referring them for biopsy, impress upon them the need to attend their appointment.
  • Establish the patient’s concern, which will usually centre on worries about cosmetic appearance or cancer. This will result in a more functional consultation and a more satisfied patient.

Red Flags

  • Night sweats and itching with skin nodules raises the suspicion of lymphoma. Examine lymph nodes, liver and spleen carefully.
  • The elderly patient complaining of a lesion in a sun-exposed area which ‘just won’t heal’ may well have a squamous or basal cell carcinoma.
  • The appearance of a nodule in a mole is highly significant and requires referral.
  • A patient with nodulocystic acne requires referral to a dermatologist for possible treatment with 13-cis-retinoic acid.
  • The unwell middle-aged or elderly patient who develops bizarre and widespread skin nodules over a period of a few weeks probably has an underlying carcinoma.
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Website disclaimer

Pulse Reference is based on the best-selling book Symptom Sorter.

The experts behind Pulse Reference are Dr Keith Hopcroft who is the co-author of Symptom Sorter, a GP in Essex and Pulse’s editorial advisor and Dr Poppy Freeman, a GP in Camden and also a clinical advisor to Pulse.

This website is for clinical guidance only and cannot give definitive diagnostic information. Practitioners should work within the limits of their individual professional practice, seek guidance when necessary and refer appropriately.