Background: ‘Atopic dirty neck' is a poorly understood acquired hyperpigmentation in patients with atopic dermatitis (AD). Objective: To report a single-centre experience with synthesis of this entity's features. Methods: All patients with AD with dirty neck seen over a 5-month period at the National Skin Centre were invited to participate. Results: Out of 544 AD patients examined, 78 (14.3%) had acquired pigmentation of the neck. The majority had moderate-to-severe underlying eczema. Histopathology showed increased epidermal melanin and dermal melanophages, a thickened basement membrane and a dense superficial perivascular infiltrate. Conclusion: Acquired atopic hyperpigmentation has a high prevalence, particularly in adolescent Asian males. Clinico-pathological correlation suggests it results from both frictional melanosis and post-inflammatory hyperpigmentation. The rippled appearance and the onset in adolescence are probably due to accentuation of the juxta-clavicular beaded lines. Optimal control of eczema may improve and potentially prevent the development, which is of importance considering the psychosocial impact of the condition.

There is a trend toward Fas-L being more prevalent in the epidermis of drug maculopapular rashes, although this did not reach statistical significance. This is possibly because of the small sample size.

We report an elderly man with hepatocellular carcinoma who developed a rash after undergoing transarterial chemoembolization (TACE). On examination, there was a reticulated macular pigmentation over the chest and upper abdomen. Skin biopsy revealed foreign material that occluded the small dermal cutaneous vessels. These structures were perfectly spherical, homogeneously eosinophilic, and were also nonrefractile. They had a maximum diameter of 40 μm, consistent with the size of the microspheres used in TACE. TACE is a palliative measure used to treat hepatocellular carcinoma in patients who are not surgical candidates. Vaso-occlusive manifestations of the skin are rare occurrences, with only 8 reported cases. Seven cases attributed this to nontarget embolization of the hepatic falciform artery and 1 case postulated that collateral supply of the targeted area allowed for hematogenous migration of the occluding beads via the microcirculation. Pertaining to treatment, all patients were treated with oral nonsteroidal anti-inflammatory agents to good effect, with 1 patient receiving additional laser treatment and another having local steroid injections. Prognosis is excellent, because the skin lesions tend to resolve within a year. Several methods have been suggested to prevent these vaso-occlusive skin complications, including prophylactic application of ice or placing the tip of the microcatheter distal to the origin of the hepatic falciform artery and falciform artery.

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Indeterminate cell histiocytosis (ICH) is an extremely rare cutaneous neoplastic disorder. It has the immunophenotypic features of both Langerhans and non-Langerhans cell histiocytosis. We report here a case of a healthy young Chinese woman who presented with disfiguring, thick, infiltrated cutaneous nodules on the face, trunk and extremities which appeared progressively over a period of 4 years. No systemic involvement has been detected so far. Results of a skin biopsy showed diffuse dermal infiltration of histiocytoid cells with indented nuclei and positive staining for S100 and CD1a and negativity for CD207 (langerin). Admixed within were some CD68-positive foamy histiocytes and multinucleated giant cells with focal expression of CD163. Although the clinical presentation is more typical of progressive nodular histiocytosis, the histology and immunoprofile is consistent with ICH. Our report adds to the limited case reports in the current literature of ICH in the Chinese population.