Inflammatory bowel diseases (IBDs) may be associated with extra-intestinal manifestations. Among these, mucocutaneous manifestations are relatively frequent, often difficult to diagnose and treat, and may complicate the course of the underlying disease. In the present review, a summary of the most relevant literature on the dermatologic manifestations occurring in patients with inflammatory bowel diseases has been reviewed. The following dermatological manifestations associated with IBDs have been identified: (i) specific manifestations with the same histological features of the underlying IBD (occurring only in Crohn’s disease); (ii) cutaneous disorders associated with IBDs (such as aphthous stomatitis, erythema nodosum, psoriasis, epidermolysis bullosa acquisita); (iii) reactive mucocutaneous manifestations of IBDs (such as pyoderma gangrenosum, Sweet’s syndrome, bowel-associated dermatosis-arthritis syndrome, aseptic abscess ulcers, pyodermatitis–pyostomatitis vegetans, etc.); (iv) mucocutaneous conditions secondary to treatment (including injection site reactions, infusion reactions, paradoxical reactions, eczematous and psoriasis-like reactions, cutaneous infections, and cutaneous malignancies); (v) manifestations due to nutritional malabsorption (such as stomatitis, glossitis, angular cheilitis, pellagra, scurvy, purpura, acrodermatitis enteropathica, phrynoderma, seborrheic-type dermatitis, hair and nail abnormalities). An accurate dermatological examination is essential in all IBD patients, especially in candidates to biologic therapies, in whom drug-induced cutaneous reactions may assume marked clinical relevance.

Allergic contact dermatitis (ACD) is a common inflammatory skin disease that, especially when the condition becomes chronic, has a high impact on the quality of life and represents a significant disease burden. ACD represents a type IV delayed-type hypersensitivity reaction that is triggered by contact with an allergen in previously sensitized individuals through the activation of allergen-specific T cells. In the acute phase, it is characterized by eczematous dermatitis, which presents with erythema, edema, vesicles, scaling, and intense itch. Non-eczematous clinical forms are also described (lichenoid, bullous, and lymphomatosis). Lichenification is the most common clinical picture in the chronic phase if the culprit allergen is not found or eliminated. ACD can be associated with both occupational and non-occupational exposure to allergens, representing approximately 90% of occupational skin disorders along with irritant contact dermatitis. Patch testing with suspected allergens is required for a diagnosis. Metals, especially nickel, fragrance mix, isothiazolinones, and para-phenylenediamine, are the most commonly positive allergens in patients patch tested for suspected ACD. The treatment goal is to avoid contact with the culprit agent and use topical and/or systemic corticosteroid therapy.

Nickel is the most common cause of contact allergy in the general population and the most frequently detected allergen in patients patch tested for suspected allergic contact dermatitis (ACD). ACD from nickel is a typical type IV hypersensitivity. Nickel allergy is mostly caused by nonoccupational exposure, such as jewelry and clothing decorations, metal tools, medical devices (mainly orthopedic and orthodontic implants, cardiovascular prosthesis), eyeglasses, utensils, keys, pigment for paint, cosmetics, and food (mainly legumes, chocolate, salmon, peanuts). Occupational exposure can involve several workers (mechanics, metalworkers, platers, hairdressers, jewelers, workers in the constructions and electronic industries), classically involving hands and forearms. The classic clinical pattern of ACD caused by nickel is characterized by eczematous dermatitis involving the sites of direct contact with the metal. Non-eczematous-patterns are reported, including lichenoid dermatitis, granuloma annulare, vitiligo-like lesions, dyshidrosiform dermatitis, and vasculitis. In the case of systemic exposure to nickel, sensitized patients could develop systemic contact dermatitis. Patch testing represents the gold standard for the diagnosis of ACD from nickel. Treatment includes avoidance of contact with products containing nickel and the patient’s education about the possible use of alternative products. A recent EU nickel directive, regulating the content and release of nickel from products, has caused a decrease of nickel contact allergy in some European countries. Nickel allergy is a relevant issue of public health with significant personal, social, and economic impact. This review summarizes epidemiology, pathomechanism, clinical patterns, treatment, and prevention programs.

Purpose: To improve the diagnostic accuracy and optimal management of pediatric melanomas. Methods: We conducted a retrospective descriptive, multicenter study of the epidemiological, clinical, and dermoscopic characteristics of histopathologically proven melanomas diagnosed in patients less than 18 years old. Data on sociodemographic variables, clinical and dermoscopic characteristics, histopathology, local extension, therapy and follow-up, lymph node staging, and outcome were collected from the databases of three Italian dermatology units. We performed a clinical evaluation of the morphological characteristics of each assessed melanoma, using both classic ABCDE criteria and the modified ABCDE algorithm for pediatric melanoma to evaluate which of the two algorithms best suited our series. Results: The study population consisted of 39 patients with a histologically confirmed diagnosis of pediatric melanoma. Comparing classic ABCDE criteria with the modified ABCDE algorithm for pediatric melanomas, the modified pediatric ABCDE algorithm was less sensitive than the conventional criteria. Dermoscopically, the most frequent finding was the presence of irregular streaks/pseudopods (74.4%). When evaluating the total number of different suspicious dermoscopy criteria per lesion, 64.1% of the lesion assessments recognized two dermoscopic characteristics, 20.5% identified three, and 15.4% documented four or more assessments. Conclusions: Contrary to what has always been described in the literature, from a clinical point of view, about 95% of our cases presented in a pigmented and non-amelanotic form, and these data must be underlined in the various prevention campaigns where pediatric melanoma is currently associated with a more frequently amelanotic form. All the pediatric melanomas analyzed presented at least two dermoscopic criteria of melanoma, suggesting that this could be a key for the dermoscopic diagnosis of suspected pediatric melanoma, making it possible to reach an early diagnosis even in this age group.