Psoriasis is distributed across the world with a prevalence ranging from 0.5% to 4.6% [1, 2]. This condition has been associated with other diseases, or comorbidities, such as oral cavity involvement, including oral lesions and periodontal disease, thus reaffirming that this is a systemic disease [3, 4]. Psoriasis is a chronic, inflammatory disease which is characterized by the exaggerated proliferation of keratinocytes as a result of immune system activation through T lymphocytes in focal cutaneous areas [5, 6].

In most cases of psoriasis, oral lesions are associated with the presence of geographic and fissured tongue, although data show an increased frequency of associations with generalized pustular psoriasis [7]. It has been estimated that the actual prevalence of fissured tongue and geographic tongue is 6 - 33% and 1-18%, respectively, suggesting that these might represent different expressions of the same disease [7]. However, there is no consensus of the clinical description of what could be considered an oral psoriatic lesion, oral evaluation, or examination, is not a regular procedure in patients with psoriasis [7, 8]. Oral lesions are generally asymptomatic, although there might be tongue swelling and pain when deep fissures are formed [7, 8]. Furthermore, bad tongue hygiene can cause halitosis and tissue swelling due to the accumulation of food residues in fissures, thus causing burning and stinging, especially after contact. However, this association is debatable because it is not known if such oral manifestations are a symptom of disease severity or represent an expression of the disease itself [8].

On the other hand, periodontal disease is marked by an exaggerated response of the immune system to oral microbiota, making it a chronic inflammatory disease which is mediated immunologically, in which immune cells cause inflammation and cellular destruction [9].

Although the two pathologies are similar from the immunological aspect, some characteristics still render them separate diseases and there is no real association known between them [10, 11]. New research has shown that both psoriasis and periodontal disease have both experienced increased prevalence worldwide, and have been associated with other diseases and comorbidities, thus reconfirming that these are, indeed, systemic diseases [12, 13]. There are no existing reports in the published literature which describe the prevalence and frequency of psoriasis and periodontal disease in Colombia. We considered that it was very important for such clinical data to be available because we believe that appropriate examinations should be carried out on all patients with psoriasis, who may have multiple associated comorbidities. We also believe that such examinations should be performed on a regular basis. Furthermore, it is not yet known if the diagnosis of oral psoriasis should be made when lesions in the oral cavity present by themselves, or only at the same time as skin symptoms develop. Consequently, in this study, we aimed to investigate the association between periodontal diagnosis, microbiological components, the presence of IgG against Porphyromonas gingivalis (P. gingivalis), and the clinical manifestations of psoriasis.

The mean age of our patients was 52.32±17.5 years, the mean measure of BMI was 26,41 ± 3,79 in the group. The distribution in separate groups by gender was the following: for men 27,33 ± 3,47 and 25,08 ± 3,9 for women (Table 1). Additionally, 62% of our patients had a body mass index (BMI) >25, and mean BMI was 26.4 ±3 kg/m². Clinically, 97% of our patients had Psoriasis vulgaris (P. vulgaris) and 23% had nail lesions. Pitting was the most frequent presentation on the nail plate (15% of patients). Risk factor analysis showed that 46% of our patients had a history of smoking and 8% were active smokers.

3.3. Oral Variables and their Association with Clinical Psoriatic Parameters

In total, 71 patients were analyzed; 91% of these patients presented with some form of lesion or anatomical variation in the oral cavity. Furthermore, 28% of patients had a single lesion and 63% presented with multiple oral lesions. Lesions associated with psoriasis were seen in 81.69% of patients, fissured tongue in 59.15% (Fig. 1A and 1B), followed by angular cheilitis 14.08%, erythematous lesions 12.67%, dry mouth (11.26%), oral burning (5.63%), geographic tongue (2.81%), and recurrent aphthae (1.40%) (Table 3).

Fig. (1). Fissured tongue.

Table 2. Distribution of dermatological lesions in patients with psoriasis

Dermatological Lesions	Total Psoriasis Group n=71
-	n (%)
Evidence of erythematous lesion on head	38(53.52)
Evidence of erythematous lesion on upper limbs	46(64.79)
Evidence of erythematous lesion on lower limbs	46(64.79)
Evidence of erythematous lesion on trunk	43(60.57)
Evidence of scaly lesion on head	35(49.30)
Evidence of scaly lesion on upper limbs	46(64.79)
Evidence of scaly lesion on lower limbs	43(60.57)
Evidence of scaly lesion on trunk	48(67.61)
Evidence of indurated lesion on head	32(45.07)
Evidence of indurated lesion on upper limbs	45(63.38)
Evidence of indurated lesion on lower limbs	42(59.15)
Evidence of indurated lesion on trunk	44(61.97)
Head extension
0-10	69(97.18)
10-30	2(2.82)
>30	0
Upper limbs extension
0-10	62(87.32)
10-30	2(2.82)
>30	7(8.86)
Lower limbs extension
0-10	26(36.62)
10-30	45(63.38)
>30	0
Trunk extensión
0-10	70(98.58)
10-30	1(1.41)
>30
Evidence of nail lesions
Presence	16(22.54)
Nail lesion type
Pitting	11(15.26)
Drop of oil	5(7.04)

When analyzing the global severity indexes PASI and DLQI, no association was found with any oral lesion. However, analyzing the type of lesion individually, it was found that fissured tongue was significantly associated with the presence of comorbidities (p=0.034). The presence of angular cheilitis in 14.49% of patients was associated with ESR (p=0.03) and oral erythematous lesions, found in 13.04% of patients, were significantly associated with erythematous manifestations in the head (p=0.029), lower limb lesions (p=0.023), scaly head lesions (p=0.014), lower limb lesions (p=0.033), and indurated head lesions (p=0.043; Table 4). No other patient presented with actinic cheilitis or oral lichen planus. Overall, 42% of patients with oral lesions had severe psoriasis.

Psoriasis is an inflammatory disease that affects between 0.5 and 4.6% of the population worldwide, with rates varying between countries and races [1, 2, 6]. Evidence for oral lesions in psoriasis is rare and controversial, although some authors have reported non-specific lesions such as fissures and geographic tongue [7, 8]. This means that these conditions are oral manifestations of psoriasis because of their similarities in terms of clinical, genetic and histological findings. Nevertheless, there has been no conclusive statistical analysis which has investigated the association between periodontal conditions and the severity or clinical type of psoriasis [8].

Oral psoriasis manifestations were first described in 1903 [9], although its true association with the disease has been the source of much debate. Nowadays, there is evidence that oral lesions within a subgroup of patients with psoriasis are associated with skin lesions [7, 13]. Fissured and geographic tongue are considered to represent the most common oral manifestation in such patients [19] and a variety of studies have reported the prevalence of fissured and geographic tongue to be 35% and 17%, respectively [19, 20]. These findings could represent manifestations of P. vulgaris, thus acting as disease markers [21].

In 2009, a Brazilian study reported that geographic and fissured tongue were the most common oral lesions in patients with psoriasis [7]. The objective of the Brazilian study was to test if the frequency of oral lesions correlated with cutaneous psoriasis. A follow-up study was carried out on patients with P. vulgaris with geographic tongue to evaluate the progression of oral and cutaneous lesions. These lesions were more frequent in the psoriasis group and were not statistically associated with the frequency of oral lesions, although these types of lesions were significantly associated with the presence of cutaneous psoriasis [22].

In another study, Picciani studied 284 psoriatic patients to ascertain the relationship between severity and the presence of geographic tongue through PASI and demonstrated that severe psoriasis occurred in 25% of patients without geographic tongue and in 58% of patients with geographic tongue [23]. This author concluded that geographic tongue may be considered as a marker of severity [23].

In comparison, the results of our present showed that most patients had some type of oral lesion or anatomical variation, in addition to psoriatic-associated lesions, and that fissured tongue was the most common lesion associated with P. vulgaris. Our findings concurred with previous studies in that fissured and geographic tongue were clinical manifestations of P. vulgaris. Moreover, fissured tongue was more prevalent in late psoriasis while geographic tongue was more prevalent in early psoriasis, suggesting that these lesions can represent an oral manifestation of psoriasis.

As with our present study, previous literature, including a Venezuelan study by Kkilikan et al. [24] involving 200 patients with oral lesions, describes the analysis of different types of psoriasis without predilection for any form of the disease and reported that this type of oral manifestation has no specific association with any subtype of psoriasis, but does have an association with the serological marker, ESR, suggesting the need to evaluate the oral cavity in patients throughout the course of the disease. However, none of the existing studies had evaluated whether there is a direct association between other oral lesions and P. vulgaris or its severity. Since true psoriatic oral lesions and nonspecific changes are mostly asymptomatic, routine examination of the oral cavity seems necessary in all patients with the diagnosis of psoriasis [25, 26].

Another oral manifestation being investigated is the pre-sence of periodontal disease, which, like psoriasis, is showing increased prevalence worldwide [27]. However, there are very few existing reports that have confirmed the prevalence and prevalence and frequency collectively [28]. Prior to the present study, no study had evaluated the relationship between periodontal disease and psoriasis severity in Colombia. Both of these conditions are chronic inflammatory and destructive disorders, characterized by dysregulation of the host immune response. The etiology of both diseases is multifactorial and susceptibility is influenced by genetic and environmental factors [29]. Furthermore, changes in the microbiota of the gingival sulcus are a distinctive characteristic of the inflammatory hypothesis [30].

In 2016, the European Academy of Dermatology and Venereology [27] demonstrated an association between psoriasis and periodontal disease. Subsequently, a Danish study, involving a 15-year follow-up period, reported patients with mild to severe psoriasis and psoriatic arthritis [31]. The objective of this earlier study was to analyze the relationship between psoriasis or psoriatic arthritis and periodontal disease. Results showed that there was an increased risk of psoriatic patients developing the periodontal disease in comparison with the general population, and also that the incidence of periodontal disease was highest in patients with psoriasis [31]. The results of this previous paper concur well with our present study relating to P. vulgaris.

Our present data further showed that it was not possible to establish a significant association between the presence of P. gingivalis, antibody titer, and psoriasis severity. However, antibodies associated with other diseases, such as rheumatoid arthritis, have previously been shown to be associated with activity markers [12].

A significant frequency of periodontal disease was detected in patients with psoriasis in mild to severe forms, affecting more than half of the patient population sampled. Nevertheless, there was no statistically significant association in this respect, although this could have been due to the relatively small number of patients due to our strict exclusion criteria, some studies found a risk of periodontitis, Patients with the psoriatic disease should receive regular periodontal evaluation [32, 33].

Furthermore, the presence of lesions in the oral cavity, and its association with the severity of psoriasis indicates that in some patients, evaluation of the oral cavity should be considered as routine, especially given the possibility of using oral lesions as severity markers in some subgroups of patients with psoriasis, including P. vulgaris. This finding demonstrates the importance of oral health and the early detection of oral lesions because this practice might help control the disease in general.

Finally, our study was designed to raise awareness in the medical community of the potential effects of oral infection on systemic conditions. Our findings highlight the importance of multi-disciplinary management between dermatologists and periodontal and oral pathology specialists, in achieving an integral approach in medical practice, which would benefit patients and public health costs.