Terra Firma-Forme Dermatosis: it's easy when you know it
- 1Department of Paediatrics, Glan Clwyd Hospital, Bodelwyddan, North Wales, UK
- 2Department of Dermatology, Glan Clwyd Hospital, Bodelwyddan, North Wales, UK
- Correspondence to Dr Markus Hesseling, Department of Paediatrics, Glan Clwyd Hospital, Sarn Lane, Bodelwyddan, North Wales LL18 5UJ, UK;
- Received 5 December 2012
- Revised 23 January 2013
- Accepted 23 January 2013
- Published Online First 14 February 2013
A 10-year-old boy presented to the outpatient department with pigmented plaques behind his ears and on his right forearm (see figures 1 and 2). He was asymptomatic and his hygiene was very good. Dermatology review of the photographs suggested a diagnosis of Terra Firma-Forme Dermatosis and a recommendation to use alcohol wipes was made. On contacting the family his mother reported that the rash had resolved following the application of almond oil thereby confirming the diagnosis.
Terra Firma-Forme Dermatosis is still sometimes referred to as Duncan's Dirty Dermatosis following the initial publication by Duncan et al.1 It is characterised by idiopathic hyperkeratosis that appears as dirt-like discolouration which cannot be removed by washing with soap and water.2
The condition is more common in children than adults and is most commonly found on neck, face and ankles.3 When suspected early, gentle rubbing of alcohol or alcohol containing solutions leads to resolution. Patients may otherwise undergo an unnecessary skin biopsy or endocrine evaluation due to concerns about a potential diagnosis of acanthosis nigricans and insulin resistance. Topical corticosteroids may be inappropriately prescribed.
This case has been reported to raise awareness amongst paediatricians of Terra Firma-Forme Dermatosis. A diagnosis made early on clinical grounds can be reassuring to families and save children from unnecessary investigations and treatments. Application of isopropyl alcohol is the simple and effective treatment of choice.
Contributors All three authors have contributed significantly to the article. MH had the idea for the article. MH and DW identified and managed the case. AR and DW conducted the literature search and AR and MH wrote the article. MH takes responsibility for the overall content as a guarantor.
Competing interests None.
Patient consent Obtained.
Provenance and peer review Not commissioned; internally peer reviewed.