Case reports and narrative fallacies: the enigma of black swans in dermatology

Narrative fallacy is a problematic heuristic that leads us to make inaccurate cause-effect relationships. They are a particular issue in case reports because of the limited scope of these papers, the perpetuated biases they proffer and the misperception of 'black swan' events. This article highlights the negative effects of these fallacies in dermatological practice through three case studies: the use of epinephrine with lignocaine at distal sites, the difference between once-daily and twice-daily application of topical steroids, and the effect of sterile gloves for skin surgery on infection rates. Awareness of the biases in case reports and the employment of metacognition may help us to avoid falling victim to narrative fallacies. Given the potential problems with this heuristic, Clinical and Experimental Dermatology (CED) utilizes case reports to further medical education and offer different clinical perspectives, rather than as a driver of medical knowledge.

Inflammatory nail conditions. Part 2: nail changes in lichen planus and alopecia areata

Nail changes are frequently seen in patients with cutaneous lichen planus and alopecia areata. This manuscript provides an updated overview on the clinical features, management and prognosis of both conditions. Searches of electronic databases PubMed and EMBASE were conducted and eligible articles were accessed. Practical management principles relevant to these two conditions are also included.

Inflammatory nail conditions. Part 1: nail changes in psoriasis

Nail changes are visible in a variety of inflammatory dermatoses. The commonest dermatological condition with nail manifestations is chronic plaque psoriasis. This two-part article reviews the nail signs in psoriasis in Part 1, and the nail changes in cutaneous lichen planus and alopecia areata in Part 2. It provides a brief summary of the salient points in the clinical features, management and prognosis of these entities, with practical recommendations that may be beneficial to all dermatologists.

Disseminated Mycobacterium simiae infection in a patient with adult-onset immunodeficiency due to anti-interferon-gamma antibodies - a case report

Background

Mycobacterial species other than Mycobacterium tuberculosis and Mycobacterium leprae are generally free-living organisms and Mycobacterium simiae is one of the slowest growing Non-tuberculous mycobacteria. This is the first case report of Mycobacterium simiae infection in Sri Lanka and only very few cases with extrapulmonary manifestation reported in the literature.

Case presentation

A 24-year-old, previously healthy Sri Lankan male presented with generalized lymphadenopathy with discharging sinuses, evening pyrexia, weight loss, poor appetite and splenomegaly. Lymph node biopsies showed sheets of macrophages packed with organisms in the absence of granulomata. Ziehl Neelsen, Wade Fite and Giemsa stains revealed numerous red coloured acid-fast bacilli within foamy histiocytes. Slit skin smear for leprosy was negative and tuberculosis, fungal and bacterial cultures of the lymph node and bone marrow did not reveal any growth. Later he developed watery diarrhea and colonoscopy revealed multiple small polyps and ulcers throughout the colon extending up to the ileum, Which was confirmed to be due to cytomegalovirus confirmed by PCR and successfully treated with ganciclovir. Positron emission tomography scan guided biopsies of the gut and lymph nodes confirmed presence of mycobacterial spindle cell pseudo-tumours and PCR assays revealed positive HSP65. The culture grew Mycobacterium Simiae. Flow cytometry analysis on patient’s blood showed extremely low T and B cell counts and immunofixation revealed low immunoglobulin levels. His condition was later diagnosed as adult onset immunodeficiency due to anti- interferon – gamma autoantibodies. He was initially commenced on empirical anti-TB treatment with atypical mycobacterial coverage. He is currently on a combination of daily clarithromycin, ciprofloxacin, linezolid with monthly 2 g/kg/intravenous immunoglobulin to which, he had a remarkable clinical response with complete resolution of lymphadenopathy and healing of sinuses.

Conclusions

This infection is considered to be restricted to certain geographic areas such as mainly Iran, Cuba, Israel and Arizona and this is the first case report from Sri lanka. Even though the infection is mostly seen in the elderly patients, our patient was only 24 years old. In the literature pulmonary involvement was common presentation, but in this case the patient had generalized lymphadenopathy and colonic involvement without pulmonary involvement.

Management of mucous membrane pemphigoid in a joint oral medicine-dermatology clinic

BACKGROUND

Mucous membrane pemphigoid (MMP) comprises a group of immunobullous diseases involving the mucosa and skin. Potential sequelae include painful mucosal erosions, vision loss and laryngeal stenosis.

AIM

To characterize the features of patients with MMP seen within an Oral Medicine setting, including clinical features, immunofluorescence results and response to treatment.

METHODS

A retrospective case note analysis was undertaken. Treatment effect was divided into response and nonresponse using predetermined adjective terms.

RESULTS

In total, 42 cases of MMP were identified (18 men, 24 women), mean age 65 years (range 36-85 years). Oral involvement was most common on the gingivae (n = 38; 90.5%) while the most common extraoral sites involved were ocular (n = 13; 31.0%) and skin (n = 12; 28.6%). Features of MMP were found in 21 of 34 (61.8%) of routine biopsies, 31 of 34 (91.2%) direct immunofluorescence samples and 8 of 25 (32.0%) indirect immunofluorescence samples. Topical corticosteroids provided effective symptom control in 9 of 42 cases (21.4%), while systemic therapy was used in 31 of 42 patients (73.8%). Dapsone was prescribed for 25 patients, of whom 18 (72.0%) responded. Mycophenolate mofetil was used in 13 cases and had a response rate of 46.2%. Overall, 27 of 42 patients (64.3%) achieved a response using a tolerable topical or systemic treatment.

CONCLUSION

This series demonstrates that MMP has a female predominance and is a disease of older age, with a predilection for specific oral sites. Direct immunofluorescence has a high sensitivity in detecting features of MMP. Although some patients achieve adequate symptom control with topical corticosteroids, many require systemic therapy.

Lichen sclerosus

Lichen sclerosus (LS) is a chronic inflammatory disorder of the skin and mucosa, presenting to genitourinary physicians and dermatologists. It affects both sexes and all age groups. Although the exact aetiology is uncertain, genetic predisposition, infections and autoimmune factors have been implicated in its pathogenesis. Symptoms include pruritis and soreness, but asymptomatic presentations are not uncommon. The classical clinical picture is of atrophic white plaques in the anogenital region. Histopathology is specific with basal cell degeneration, upper dermal oedema, homogenization of collagen and a chronic inflammatory infiltrate. Short courses of potent topical corticosteroids form the mainstay of treatment. The condition tends to be remitting and relapsing, with spontaneous regressions reported in a few. In men, the term balanitis xerotica obliterans is sometimes used to describe late and severe LS of the penis. Scarring and progression to squamous cell carcinomas can occur in chronic LS, resulting in significant morbidity. A multi-disciplinary approach to care and the need for long-term monitoring cannot be over-emphasized.

Behçet's disease

Behçet's disease (BD) is a chronic, relapsing multisystem vasculitis with predominant involvement of the oral and genital mucosa. It has a worldwide distribution, but the prevalence is highest in Central Asia and the Far East (along the ancient 'Silk Route'). Genetic, environmental, immunological and haemostatic factors play a role in the aetiopathogenesis. The International Study Group for BD proposed criteria for the diagnosis of this condition, the essential feature being recurrent oral ulceration. Genital ulcers and skin manifestations are common, while ocular changes are the most important cause of morbidity. Almost any organ in the body can be involved, and systemic involvement may portend a poorer prognosis. There is no pathognomonic test for BD and the diagnosis is made on clinical findings. Treatment of BD would require multidisciplinary cooperation, and early referral to an ophthalmologist is advisable to prevent ocular morbidity. Topical and systemic agents (colchicine, dapsone and thalidomide) are useful in controlling exacerbation of the oral and genital ulcers. Severe disease may require immunosuppressive agents and, more recently, biological agents have been used successfully. It tends to follow an unpredictable course, and the eventual prognosis depends on the systemic involvement.

In search of oral psoriasis

Even though psoriasis is a common skin disorder, reports of it involving the oral cavity are exceedingly rare, with less than 100 publications in the literature. Biopsy-proven oral psoriasis has been reported in the oral medical literature, but the commonest oral mucosal findings in most studies are associated non-specific features including fissured and geographic tongue. Case series on this entity have not provided any definitive data to support its existence. From the evidence available to date, it is still unclear if oral psoriasis is a distinct entity or if, indeed, it exists.

Imiquimod use in the genital area and development of lichen sclerosus and lichen planus

Imiquimod has immune-stimulant properties that can precipitate autoimmune conditions like eczema, psoriasis and lichenoid conditions. We report two cases here where imiquimod induced florid lichen sclerosus in one patient and lichen planus in another. In both patients the condition was so aggressive and unresponsive to steroid treatment that circumcision was necessary.

Treatment of recalcitrant plantar warts with imiquimod

Myrmecia are viral warts that result from the coalescence of plantar or palmar warts into large plaques. Treatment of these warts involves physical or chemical destruction of the verrucae, potent keratolytics or immunotherapy. Imiquimod 5% cream is a novel topical immunomodulator that has been used successfully in the treatment of genital and common warts. We report its successful use in a 35-year-old immunocompetent man who had had resistant plantar warts for 15 years.

Tufted angioma in a case of neurofibromatosis type I

Tufted angiomas are rare benign tumours with a characteristic histopathological appearance. Their occurrence in neurofibromatosis type 1, a genodermatosis in which vascular malformations are not uncommon, has hitherto not been reported. Some of the characteristic features of tufted angiomas are discussed.

Interface dermatitis in a patient with AIDS

Interface dermatitis is a histological reaction pattern which is seen in a number of conditions. One of the recent associations of the histology is in Acquired Immune Deficiency Syndrome. There are differentiating factors between interface dermatitis occurring in AIDS and those occurring in other conditions. These are discussed in detail.

Postpemphigus acanthomata: a sign of clinical activity?

BACKGROUND

Pemphigus is a group of vesiculobullous disorders in which the blisters usually heal with hyper or hypopigmentation. The appearance of acanthomata at sites of previous blisters has been noted in some cases.

METHODS

All cases of pemphigus admitted to the Madras Medical College hospitals during a 2-year period from March 1993 to March 1995 were taken into the study and screened for the presence of acanthomata.

RESULTS

Fifty-two cases of pemphigus were identified, 47 of pemphigus vulgaris and five of pemphigus foliaceus; and of these 13 developed acanthomata when the blisters healed. Ten of these cases were of pemphigus vulgaris and three were of pemphigus foliaceus; biopsy of these lesions showed hyperkeratosis, acanthosis, papillomatosis, and intraepidermal clefting. Immunofluorescence carried out in two of these acanthomata also showed intercellular fluorescence.

CONCLUSIONS

The occurrence of acanthomata in healed lesions of pemphigus is not uncommon; because histopathologic and immunofluorescence evidence of disease activity is present, cases of this sort require careful follow-up.

Atypical dyskeratosis congenita

Dyskeratosis congenita is a syndrome characterised mainly by pigmentation and atrophy of skin, nail dystrophy and oral leucoplakia. We report a patient who had features consistent with this syndrome including skin atrophy and pigmentation, oral leucoplakia, oesophageal stricture, but with normal finger and toe nails. Even though many variants have been described in the literature sparing of the nails as in our patient is extremely uncommon.