Pictorial case studies: Four presentations of skin conditions

Diagnosis, differential diagnosis and management of four cases. By Dr Brian Malcolm

Figure 1: Cutaneous sarcoidosis (Images: Dr Brian Malcolm)

Cutaneous sarcoidosis

This 46-year-old patient was being investigated by respiratory and dermatology specialists. She had a mildly itchy, papular eruption on her forearms for about 12 months, which had been labelled papular eczema, but then developed an unexplained cough and dyspnoea. Her rash progressed, with linear streaking of the palms. An X-ray demonstrated hilar lymphadenopathy and the histology of a skin biopsy was typical of sarcoid.



Clinical features, differential diagnosis and management

In my experience, no two presentations of sarcoidosis are the same. Dermatologically, the diagnosis should be considered when there are indurated/infiltrated nodules or plaques, which may be erythematous but are more characteristically violaceous. 

Sarcoid is also one of the differential diagnoses when a patient presents with erythema nodosum, which is usually an early manifestation of the disease. As with the cutaneous signs, the systemic features are protean. 

Any organ can be affected and the course can be protracted, but it is most commonly benign. The highest prevalence is in the 20-40 year age group, with a slight female bias. Symptoms are often non-specific – fatigue, weight loss and general malaise, with respiratory symptoms in about half of all patients. A third of cases may develop skin lesions, whose severity does not correlate with the extent of systemic involvement. 

Cutaneous lesions can be macular-papular, nodular and annular or subcutaneous. Lesions can exhibit koebnerisation. Infiltrative disease of the nose, lupus pernio, is quite common. More rare morphologies include erythrodermic, ichthyosiform, lichenoid and verrucose forms. The aetiology remains obscure.

The mainstay of treatment is steroids, both oral and topical.

Figure 2: Flexural lichen planus (Images: Dr Brian Malcolm)

Flexural lichen planus

This 73-year-old woman presented with a symmetrical eruption composed of purplish/brown flexural patches in the axillae and groins, and also involving the submammary and abdominal folds. This had gradually evolved over the preceding months and was entirely asymptomatic. 

She was otherwise fit and well and not taking any regular medication. Mucosal surfaces, hair and nails were normal. 

An initial differential diagnosis of atrophic lichen planus, or a possible subtle acanthosis/pseudoacanthosis nigricans, was made, although clinically there was an absence of any textural change in the skin and no relevant comorbidities. Histology strongly supported the diagnosis of lichen planus.


Flexural lichen planus

Clinical features, differential diagnosis and management

This was an unusual presentation of a condition that, although not common, is regularly encountered in secondary care dermatology. The particular feature here was involvement of the abdominal skin folds. 

Lichen planus has a wide range of presentations and is very variable in terms of symptoms, ranging from being intensely itchy to, as in this case, completely asymptomatic. The range of treatments includes steroids, both topical and systemic, phototherapy and retinoids. In this case, no active treatment was indicated and spontaneous resolution was awaited. 

Figure 3: Erosive pustular dermatosis of the scalp (Image: Dr Brian Malcolm)

Erosive pustular dermatosis of the scalp

This 84-year-old man had been treated for a number of cutaneous malignancies in the past. He was referred urgently with a rapidly developing crusted area on his scalp. 

This was debrided in clinic to reveal a superficially eroded area with an exudative base. A diagnosis of erosive pustular dermatosis was suspected clinically. Two mapping biopsies demonstrated acute inflammatory changes only.


Erosive pustular dermatosis

Clinical features, differential diagnosis and management

This condition most commonly affects women over the age of 70 years. It can be clinically quite alarming, because first impressions can be of rapidly progressive and surgically challenging malignancy. 

The condition tends to affect the same group of patients where skin cancers are most prevalent, that is, those with Fitzpatrick skin types I and II with extensive photodamage. 

Involvement also has a predilection for areas of scarring, such as postoperative or following shingles. 

Histology demonstrates erosion and a chronic inflammatory dermal infiltrate. It is important to be aware of potential sampling error missing malignant change. 

With experience, the condition can be more confidently clinically suspected and a short cycle of superpotent topical steroids initiated, reserving biopsy for non-responders. In this case, the area completely resolved following application of clobetasol 0.05% cream twice daily for two weeks.

Figure 4: Merkel cell tumour (Image: Dr Neil Shroff)

Merkel cell tumour

This 79-year-old man presented with a very short history of a few weeks of a rapidly growing, firm nodule on his left wrist. This was asymptomatic. Such lesions should be managed according to the EFG (Elevated, Fixed or Firm and Growing) rule of obtaining urgent histology.


Merkel cell tumour 

Clinical features, differential diagnosis and management

These tumours arise from Merkel cells of neuroendocrine origin and are considered uncommon, but their incidence is rising because of the ageing demographic. The mean age at diagnosis is 74 years, with a slight preponderance of males. 

They usually manifest as rapidly growing blue/red nodules. The clinical appearances are not distinctive. They arise most commonly in sun-exposed sites, especially in the presence of immunosuppression, but can occur on any part of the body. 

The prognosis is poor because they are locally aggressive and recurrent, but also at high risk of metastatic spread through the lymphatics. Mortality rates of up to 30-50% are quoted. Treatment centres on wider local surgical excision with or without sentinel node biopsy. Radiotherapy can help in local disease control and palliation. 

  • Dr Brian Malcolm is an associate specialist and GPSI in dermatology in Barnstaple, Devon, honorary associate lecturer, Cardiff University, and committee member of the Primary Care Dermatology Society
  • Acknowledgments: Thanks to Dr Neil Shroff for contributing figure 4 

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