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Inflammatory dermatoses affecting the nail
Published in Eckart Haneke, Histopathology of the NailOnychopathology, 2017
Chronic allergic contact dermatitis may be difficult to differentiate from nail lichen planus as there is a dense band-like epidermotropic infiltrate; this, however, does not cause liquefaction degeneration of the basal cells in eczema as opposed to lichen planus. Alopecia areata of the nails is essentially a spongiotic dermatitis. Sometimes, no differentiation is possible on histologic grounds alone. Paronychia due to yeasts or molds may look similar to chronic eczema and a PAS stain may be necessary to make the correct diagnosis. Psoriasis may rarely cause difficulties in the clinical differential diagnosis but is usually diagnostic enough to make the correct diagnosis. Onychomycoses also lead to spongiosis, sometimes even spongiotic vesicles, hyperkeratosis, and serum inclusions as well as Munro microabscess-like accumulations of neutrophils; a PAS or Grocott stain may be necessary. Nevertheless, onychomycoses poor in fungal elements may be overlooked.
Angiogenesis and Roles of Adhesion Molecules in Psoriatic Disease
Published in Siba P. Raychaudhuri, Smriti K. Raychaudhuri, Debasis Bagchi, Psoriasis and Psoriatic Arthritis, 2017
Asmita Hazra, Saptarshi Mandal
The marked dilation of dermal vessels in psoriatic lesions was mentioned at least as early as 1896 by Unna, and some of the capillary morphology work predates Folkman’s works on angiogenesis (Telner and Fekete 1961). A detailed description of dermal microvascular growth in psoriasis by Braverman is almost contemporary to the original works of Folkman in the early 1970s. Braverman (1972, 2000) demonstrated very nicely that the dermal vascular loops elongate in psoriatic plaques by venulization, that is, grow exclusively from the venous end and show ultrastructural features of bridge fenestrations and a multilayered basement membrane. But uninvolved skin of psoriasis patients and healed lesions have normal loops, with most of the length of an arteriolar capillary nature. The ultrastructural features of the capillary loops in pustular psoriasis and psoriasis vulgaris are not different according to Braverman. The loops in the psoriatic plaque are more tortuous than normal loops, and the ascending and descending loops are generally twisted one or two turns around each other. The crest, instead of a normal hairpin loop, forms a broad curve, sometimes with sinuous tortuosity in planes at various angles to the loop, and usually shows the highest density of bridge fenestrations. The loops become twice or thrice the normal diameter, with the descending portion sometimes reaching 20–30 μm diameter, compared with the normal 3.5–6 μm throughout the loops, with the crest and descending loop wider by 1–1.5 μm. It is from this very large-diameter part that the diapedesis, especially of neutrophils, lymphocytes, and macrophages, takes place. The neutrophils emigrate into the epidermis to form Munro’s microabscess in the stratum corneum and spongiform pustules of Kogoj in the stratum spinosum.
Generalized pustular psoriasis is a disease distinct from psoriasis vulgaris: evidence and expert opinion
Published in Expert Review of Clinical Immunology, 2022
Hervé Bachelez, Jonathan Barker, A. David Burden, Alexander A. Navarini, James G. Krueger
GPP has a clinical appearance that is dominated by the visible appearance of white/yellowish pustules that contain mainly neutrophils on microscopic examination (Figures 1 and 2). In fact, the histologic appearance of GPP is dominated by the presence of neutrophils, which can appear as extensive accumulations in or just under the stratum corneum (with clinical correlate as ‘lakes of pus’) (Figure 2) [2,3,63–65]. More discrete macroscopic pustules contain large vesicles packed with neutrophils that are seated in the mid-epidermis (spinous layer; Figure 2). This neutrophilic structure is much larger and more deeply invades into the epidermis than the Munro’s microabscess in PV. The deep-seating pustule in GPP has been named ‘the spongiform pustule of Kogoj’ and its presence is uniquely diagnostic of GPP [2,28]. Hence, pustulation, and not excess scaling of the epidermis, is one of the main differential features of GPP versus PV [3].
Protective effect of a topical sunscreen formulation fortified with melatonin against UV-induced photodermatitis: an immunomodulatory effect via NF-κB suppression
Published in Immunopharmacology and Immunotoxicology, 2019
Nilutpal Sharma Bora, Bhaskar Mazumder, Santa Mandal, Yangchen D. Bhutia, Sanghita Das, Sanjeev Karmakar, Pronobesh Chattopadhyay, Sanjai K. Dwivedi
Figure 2 demonstrates the histopathological features of the excised skin samples of the back of the experimental rats. Figure 2(a,b) reveals the presence of Munro’s microabscess, rete ridges elongation, and capillary loop dilation along with the presence of thick and confluent parakeratosis, neutrophil, and lymphocyte infiltration; with the UV exposed group. These manifestations were not present in the normal and test formulation treated groups (Figure 2(c,d), respectively). The epidermal thickness of the UV exposed group was also observed to be increased up to 169.81% when compared with the normal group, whereas the test formulation showed a significant decrease (p ˂ .01) in epidermal thickness when compared with the control (UV) group. The placebo-treated group (Figure 2(e)) also showed the presence of elongated rete ridges and dilated capillary along with a severe increase (163.45%) in epidermal thickness. The standard formulation (Figure 2(f)) showed a decrease in epidermal thickness when compared with the control (UV) group; however, these differences were not found to be statistically significant. Moreover, the presence of dilated capillary was evident in the standard group.