Pemphigus vegetans of the folds (intertriginous areas).

Pemphigus vegetans (P Veg), the rarest form of pemphigus, is thought to be a variant of pemphigus vulgaris (PV). Classically, two subtypes of P Veg are recognized: (1) Neumann P Veg, which usually begins as PV with vesicles and bullae that rupture to form hypertrophic granulating erosions, then evolving into vegetating exuding masses; (2) Hallopeau P Veg, initially characterized by pustular lesions that, after rupturing, merge and gradually evolve into vegetating erosions with a centrifugal expansion. The disease typically affects the big folds (axillary, inframammary, inguinocrural, intergluteal), where semiocclusion, maceration, and mixed infections continuously incite exudation and granulation tissue formation (wet P Veg). In nonintertriginous locations, the vegetating buttons can dry out to change into warty, fissured, painful, seborrheic keratosis-like lesions (dry P Veg). Histologic examination indicates hyperplastic epidermis with intramalpighian leukocyte microabscesses and indistinct traits of suprabasal acantholysis. Immunofluorescence findings are similar to those of PV. Diagnosis is straightforward when PV lesions coexist. Difficulties can arise in cases with nonflexural location. Cytology (Tzanck test), histology, immunofluorescence, and ELISA search for anti-desmoglein antibodies are the diagnostic laboratory tools. Systemic treatment is similar to that for PV, high-dose steroids being the first choice therapy. Immunosuppressive agents and etretinate may allow a steroid-sparing effect. Topical treatment is aimed at countering the granulation tissue formation by means of several strategies (sublesional steroid injection, application of medicated gauzes in the involved flexures, chemical cautery or surgical excision of vegetating lesions).

Cutaneous sarcoidosis: an intriguing model of immune dysregulation.

Sarcoidosis is a systemic granulomatous disease characterized by the presence of non-caseating granulomas. Its etiology remains obscure. A plausible hypothesis suggests that a complex interplay of host factors, infectious processes, and non-infectious environmental factors, matched with a susceptible genetic background, results in a pathway that leads to systemic granulomatous inflammation. Although presentations of sarcoidosis vary enormously, multi-organ involvement is a common feature. Cutaneous involvement occurs in about 25% of patients with protean manifestations and variable prognoses. Skin manifestations are divided into specific lesions with histopathologically evident non-caseating granulomas and nonspecific lesions arising from a reactive process that does not form granulomas. A peculiar form of cutaneous sarcoidosis is represented by sarcoidal lesions at sites of trauma that has caused scarring. The pathogenesis of scar sarcoidosis remains unknown. Scar sarcoidosis is also associated with herpes zoster infection, surgery, and tattooing. Such heterogeneous events, along with those at the sites of chronic lymphedema, thermal burns, radiation dermatitis, and vaccinations, occur on areas of vulnerable skin labeled "immunocompromised districts". Numerous options are available for the treatment of cutaneous sarcoidosis. Although corticosteroids remain the treatment of choice for initial systemic therapy, other nonsteroidal agents have proven effective and therefore useful for long-term management. Tumor necrosis factor-α antagonists such as infliximab may have a role in the treatment of cutaneous sarcoidosis, especially in refractory cases that are resistant to standard regimens. Elucidation of the relationship of sarcoidal granulomas with malignancy and immunity may facilitate a better understanding of some pathomechanisms operating in neoplastic and immunity-related disorders.

Viruses and pemphigus: an intriguing never-ending story.

Virus infections and autoimmunity have long been linked. As to pemphigus, many studies have been directed to prove or rule out the possibility of viral induction. Herpesviruses have often been related to the onset or reactivation of pemphigus. The association may be (i) casual, (ii) due to the iatrogenic immunosuppression facilitating opportunistic viral infections or (iii) based on a pathogenic link between the viral presence and the host's dysregulated immune response leading to autoimmunity. Japanese researchers, using real-time polymerase chain reaction, lately detected herpes simplex virus DNA in the saliva from pemphigus patients at the earliest stage of the disease and with no signs or history of herpetic infection, thus confirming the possible existence of cases of pemphigus induced by herpesviruses. These selected cases could be included into the innovative concept of 'paraviral eruptions', where an inciting role for induction may be played by the concomitant intake of certain drugs.

Wolf's post-herpetic isotopic response: Infections, tumors, and immune disorders arising on the site of healed herpetic infection.

Herpes simplex viruses (HSV-1/HSV-2) and varicella-zoster virus (VZV) have several characteristics in common. Both are epidermoneurotropic, cause skin eruptions accompanied by sensory symptoms (itch, pain), damage peripheral sensory nerve fibers and cutaneous nerve endings, and interfere with neuromediator release, which can alter local mechanisms of immune control. For this reason, herpes-infected areas may become a preferential location for the subsequent onset of immunity-related skin disorders (infections, tumors, and dysimmune reactions), an event first reported by a neurologist and focused on by two brothers, a dermatologist and a pediatrician. The phenomenon therefore named Wolf's post-herpetic isotopic response (PHIR) refers to the occurrence of a new skin disorder at the site of a previous and already healed herpetic eruption (herpes zoster in most cases). Until now, we have been able to gather 189 well-documented cases of PHIR (all reported in the reference section), but our list is far from being complete. Some of the most emblematic cases are briefly described here. In some circumstances, the opposite of PHIR occurs, with diffuse skin disorders or eruptions that selectively spare herpes-infected areas (Wolf's post-herpetic isotopic nonresponse). Experimental investigations with patch testing have been performed in seven patients who were sensitized to nickel and had had herpes zoster in the past years. The tests were carried out bilaterally on the affected dermatomes and on the unaffected contralateral ones. The uneven immune responses we obtained have shown that the immune behavior of an herpes zoster-affected dermatome can be different from that of the corresponding contralateral dermatome, thus supporting the existence of immune dysregulation in herpes-infected areas.

Wolf's isotopic response: The first attempt to introduce the concept of vulnerable areas in dermatology.

The term isotopic response was coined in 1995(1) to describe the occurrence of a new skin disorder at the site of another, unrelated, and already healed skin disease. That publication paved the way to recognition of this phenomenon by the medical community worldwide with multiple reports describing it under a variety of conditions. The term isotopic response, however, turned out to be unsuitable for a Medline search, because it generated hundreds of references linked with radioactive isotopes. To facilitate Medline searches for this dermatologic phenomenon by avoiding unnecessarily time-consuming sifting through so many unrelated references, it was suggested that the name Wolf be added. The name Wolf's isotopic response has since been generally accepted and even included in Stedman's Illustrated Dictionary of Dermatology Eponyms. Although the concept of the isotopic response was conceived as being analogous to Köbner's isomorphic response, and despite the similarities between the two terms, the similarities are only "skin deep," and there is a major difference between the two. Isomorphic response means "the same morphology" (as that of the existing disease) and describes the appearance of the same disease at another location. The term isotopic response describes the appearance of an altogether different disease at the site of an already healed skin disease. We describe this entity and present representative clinical examples. Some problems in the definition of Wolf's isotopic response are provided, with special emphasis on its overlapping with Köbner's isomorphic response. The description of Wolf's isotopic response, which is analogous but not identical to the isomorphic response described some 120 years ago by Köbner, illustrates the contribution of morphologic findings and original ideas in keeping up with the ongoing progress in the field of dermatology.

The immunocompromised district in dermatology: A unifying pathogenic view of the regional immune dysregulation.

Besides the systemic immune deficiency, a sectorial default in immune control may occur in immunocompetent subjects. This regional immune defect can appear and remain confined to differently damaged skin areas, lately labeled immunocompromised districts (ICDs). An ICD is a skin area more vulnerable than the rest of the body for genetic or acquired reasons. Its vulnerability mainly consists in a local dysregulation of the immune control, which often facilitates (but sometimes hinders) the local onset of immunity-related eruptions or skin disorders. The factors responsible for localized immune dysregulation are multifarious, being represented by chronic lymphatic stasis, herpetic infections, ionizing or ultraviolet (UV) radiations, burns, all sorts of trauma (especially amputation), tattooing, intradermal vaccinations, and others of disparate nature (eg, paralytic stroke, poliomyelitis). Whatever the cause, in time an ICD may become a vulnerable site, prone to developing opportunistic infections, tumors, or dysimmune reactions (often of granulomatous type), strictly confined to the district itself; however, the opposite may also occur with systemic immune disorders or malignancies that selectively spare the district. In any case, the immunologic behavior of an ICD is different from that of the rest of the body. The pathomechanisms involved in this sectorial immune destabilization may reside in locally hampered lymph drainage that hinders the normal trafficking of immunocompetent cells (eg, chronic lymphedema, posttraumatic lymph stasis) or in a damage to sensory nerve fibers that release immunity-related peptides (eg, herpetic infections, carpal tunnel syndrome), or in both conditions (eg, amputation stump, radiation dermatitis). The ICD is a conceptual entity with no definite shape or dimension. It may take an extremely variable form and extent depending on the causative agent, ranging from a minimal area (eg, intradermal vaccination) or a small area (eg, herpes simplex infection), through a wide area (eg, radiotherapy), a bandlike segment (eg, skin mosaicism, herpes zoster infection), or an acral area (eg, carpal tunnel syndrome), up to a whole limb (eg, Stewart-Treves syndrome) or even an entire half body (eg, brain stroke). Varied newly coined terminology can be used to indicate the specific cause each time that it is responsible for a regional immune dysregulation. The advantage of the umbrella term ICD is that it encompasses all the possible causes involved in a local immune destabilization. An ICD may have a congenital or a postnatal origin, and interesting similarities between the two forms exist. An ICD may also take place in patients with a preexisting systemic immune deficiency, thus creating a more vulnerable site in an already vulnerable patient. Identifying a cutaneous ICD in a given patient is an important standpoint for both diagnostic and prevention purposes. This can be proven by the educative clinical examples that are reported here.

Alterations of skin innate immunity in lymphedematous limbs: Correlations with opportunistic diseases.

Lymphedematous areas are sites of regional immune destabilization depicting a typical example of an immunocompromised cutaneous district (ICD). This study evaluates the expression of some components of the skin innate immunity on lymphedematous limbs with the aim to clarify some facets of the ICD. Patients selected underwent two skin biopsies: One was obtained from the limb affected by lymphedema, another from the contralateral healthy limb. Expression of some components of the skin innate immunity was analyzed by reverse transcription-polymerase chain reaction. Stronger gene expression of Toll-like receptor 2 (TLR-2), human ß-defensin 2 (HBD-2), desmoglein 1, desmoglein 3, matrix metallopeptidase 9 (MMP-9), and interleukin 10 (IL-10) was found in keratinocytes derived from the affected limb compared with that of keratinocytes derived from contralateral healthy limb. Downregulation of survivin and vasoactive intestinal polypeptide (VIP) gene expression was found in the affected limbs. No induction of IL-1α and tumor necrosis factor α (TNF-α) was detectable in keratinocyte cultures obtained from both lymphedematous and normal limbs. Different phases and components of skin innate immunity turned out to be altered in the lymphedematous sites. Molecular alterations were similar in all patients recruited in the study. These changes might favor the local appearance or progression of opportunistic diseases such as tumors, infections, and immune-mediated skin disorders.

Clinical and cytologic features of antibiotic-resistant acute paronychia.

BACKGROUND: Acute paronychia usually is treated as a bacterial infection, but antibiotic-resistant acute paronychia may be caused by other infectious and noninfectious problems. OBJECTIVE: We sought to describe the clinical, etiologic, cytologic, and therapeutic features of antibiotic-resistant acute paronychia. METHODS: A retrospective review of medical records and cytology was performed in 58 patients (age, 1 month-91 years; 36 children and adolescents [62%] and 22 adults [38%]) who had antibiotic-resistant acute paronychias. RESULTS: Causes of paronychia included bacteria (25 patients [43%]), viruses (21 patients [36%]), fungi (5 patients [9%]), drugs (3 patients [5%]), pemphigus vulgaris (3 patients [5%]), and trauma (1 patient [2%]). Diagnostic cytologic findings were noted in 54 patients (93%); no diagnostic cytologic findings were present with drug-induced (3 patients) or traumatic (1 patient) paronychia. The most common predisposing factors were the habits of finger- or thumb-sucking (14 patients [24%]) and nail-biting (11 patients [19%]). Complications included id reaction with erythema multiforme in 3 patients (5%). LIMITATIONS: Limitations include retrospective study design from 1 treatment center. CONCLUSION: Antibiotic-resistant acute paronychia may be infectious or noninfectious. Cytologic examination with Tzanck smear may be useful diagnostically and may prevent unnecessary use of antibiotics and surgical drainage.

Monolesional Kaposi sarcoma at the site of slow healing herpes zoster in an HIV+ patient: immunocompromised district in an immunocompromised patient.

Besides the well-known systemic immune deficiency, also a regional immune deficiency, labeled as "immunocompromised district" (ICD), has been documented and focused in the recent years. The objective of the study is to gain more insights into the mechanisms involved in systemic and local immune destabilization. A 35-year-old, homosexual, and drug-addicted HIV+ man presented with a single nodule of Kaposi sarcoma (KS) located on the penis, where a slow to heal herpes zoster had appeared 2 months before. It has been assumed that the unusual penile location of herpes zoster facilitated the outbreak of KS in the affected dermatome because of a viral damage to sensory nerve fibers of the same dermatome. This damage, by interfering with the immunoregulatory function of neuropeptides released by nerve endings in that area, may have caused a regional alteration of the immune control favoring the local onset of the "opportunistic" angiogenic tumor (KS). In a few words, an ICD took place in an immunocompromised patient, thus introducing a more vulnerable site in an already vulnerable subject. The present case is the second one in the literature to document an ICD in the setting of preexisting systemic immune deficiency.

Pemphigus: associations and management guidelines: facts and controversies.

Pemphigus, a prototypical organ-specific human autoimmune disease, may be associated with other immunity-related disorders, viral infections, and different types of tumors. Coexistence with immune diseases is fairly frequent and, for some of them (eg, myasthenia gravis, Basedow's disease, rheumatoid arthritis, or lupus erythematosus), common pathogenic mechanisms can be considered. The association with viral infections (mainly herpesvirus infections) raises the question of whether the virus triggers the outbreak of the disease or simply complicates its clinical course. Neoplastic proliferations coexisting with pemphigus have a different histogenesis and the pathogenic link may vary according to the associated tumor (thymoma, lymphoma, carcinoma, or sarcoma). A subset of pemphigus-neoplasia association is represented by Anhalt's paraneoplastic pemphigus, with peculiar clinical, histologic, and immunologic features characterizing it. Coexistence of pemphigus with Kaposi's sarcoma, albeit not frequent, offers an intriguing speculative interest. The cornerstone of management in pemphigus is the combination of systemic corticosteroids and immunosuppressants. The conventional treatment used in most cases is based on oral administration of deflazacort and azathioprine. In selected cases, mycophenolate mofetil is preferred to azathioprine. Severe forms of pemphigus require intravenous pulse therapy with dexamethasone (or methylprednisolone) and cyclophosphamide. In the recent years, the use of high-dose intravenous immunoglobulin therapy has gained several consents. Rituximab, a monoclonal anti-CD 20 antibody, which affects both the humoral and cell-mediated responses, has proved to give a good clinical response, often paralleled by decrease of pathogenic autoantibodies. The combination with intravenous immunoglobulin offers the double advantage of better clinical results and a reduced incidence of infection. Interventional treatments, such as plasmapheresis and extracorporeal immunoadsorption, are aimed at patients with life-threatening forms of pemphigus and high levels of circulating autoantibodies, a circumstance where the medical therapy alone risks failing. Second-line treatments include gold salts (which we do not favor because of the acantholytic potential inherent in thiol structure) and the association of oral tetracyclines with nicotinamide, which is rather safe. Local treatments, supplementary to the systemic therapy, are aimed at preventing infections and stimulating reepithelialization of eroded areas. Innovative topical treatments are epidermal growth factor, nicotinamide gel, pimecrolimus, and a proteomics-derived desmoglein peptide. Pemphigus patients should be warned against over-indulging in unnecessary drug intake, prolonged exposure to ultraviolet rays, intense emotional stress, and too spiced or too hot foods. Cigarette smoking is not contraindicated in pemphigus patients because of the nicotine anti-acantholytic properties.