Table 2.

Concomitant Diseases Associated with Palmoplantar Pustulosis

Concomitant Diseases
Thyroid Disease	Parathyroid Disease	Metabolic Syndrome	Arthritis	Coeliac Disease	Quality of Life and Psychiatric Disorders
There is an association between PPP and thyroid dysfunction (prevalence of 20–40%)73 More in women with PPP (about 25% of women had thyroid dysfunction, however, thyroid values with abnormal levels in at least one analysis can be found in 43.59% of cases). The thyroid disorders found include hyperthyroidism, hypothyroidism, struma nodosa and any thyroid surgery. It is important to screen thyroid functions in PPP.11	Mainly in women with PPP In PPP patients (when compared with controls), serum calcium can be increased and parathormone can be decreased.69 Another study showed low values of 1.25 - hydroxyvitamin D3.69 PPP does not appear to be associated with changes in bone mineral density or the development of osteoporosis.74 The clinical significance and mechanisms for high serum calcium levels remain unknown.74	Prevalence of metabolic syndrome (MS)* in PPP: about 25%.75 Prevalence of obesity**: 18–62%.75 Diagnosis of PPP <40 years seem to have higher BMIs.76 Obesity may be a critical factor in PPP, specially in younger patients. Prevalence of DM2: 7.7 to 19% of PPP patients.76 It seems that there are no significant differences between fasting blood glucose and insulin in PPP patients and controls.76 Incidence of hyperlipidemia: 10.2 to 49%.77 Prevalence of hypertension and ischemic heart disease: 28.5–38.3% and 12.7–24.6%.76	Arthralgia and arthritis are relatively common problems in PPP. A study showed 42.37% prevalence of arthralgia.4 Most typical osteoarticular manifestations of PPP are hyperostosis, inflammatory synovitis, osteitis, pseudo-septic arthritis, spondylitis or spondylodiscitis.76 Prevalence of psoriatic arthritis 10–25.6%.76 Also associated with synovitis-acne-pustulosis-hyperostosis-osteomyelitis syndrome (SAPHO)***. SAPHO syndrome and other spondylopathies, such as psoriatic arthritis, seem to be related to the HLA B27 antigen.76	It is uncertain if gluten intolerance plays a role in the pathogenesis of PPP.5 Swedish studies showed: high prevalence of antigliadin, anti-tissue transglutaminase antibodies and celiac disease in patients with PPP (not routinely made on patients with PPP.5 Adherence to a gluten-free diet may lead to improvement of lesions – slow, but persistent for years (mechanism is unknown).76 Different results in German and Polish populations (due to ethnic diversity between the populations) - did not detect anti-gliadin or anti-transglutaminase antibodies in patients with PPP.76	Lesions of PPP often cause pain and itching, leading to a decrease in health-related quality of life (HRQoL). PPP affects a body area with enormous functional importance – this leads to a serious impact on the quality of life.10 Most common psychiatric disorder in PPP patients is depression (13–28.8%).77 Other psychiatric disorders that accompany PPP are schizophrenia, bipolar disorder, eating disorders and anxiety.77

Notes: * Metabolic syndrome (MS) can be defined as risk factors that enhance the risk of type 2 diabetes mellitus (DM2) and cardiovascular diseases. ** Obesity (defined as body mass index [BMI]> 25 mg/m2). *** SAPHO syndrome is part of a group of spondyloarthropathies. It is characterized by osteoarticular manifestations with or without lesion in the skin characterized by the coexistence of acne, synovitis, PPP, osteitis and hyperostosis.⁷⁶ Skin lesions can occur earlier, simultaneously or later than osteoarticular symptoms. Usually, the period between the appearance of the lesions and the osteoarticular symptoms does not exceed 2 years. The etiopathogenesis of the SAPHO syndrome remains elusive.⁷⁶

Abbreviation: ACE, angiotensin-converting enzyme; Ach, acetylcholine; AGEP, acute generalized exanthematous pustulosis; CARD14, family member of the caspase 14 recruiting domain; CLA, cutaneous lymphocyte-associated antigen; CXCR2, IL-8 receptor type B; DITRA, deficiency of the IL-36 receptor antagonist; EPQ, Eysenck Personality Questionnaire; ESIF, erythema, clinical scale, hardening and cracking; ESTEEM, Efficacy and Safety Trial Evaluating the Effects of Apremilast in Psoriasis; G-CSF, granulocyte colony-stimulating factor; GPP generalized pustular psoriasis; IFN- γ, gamma interferon; IL-36RN, IL-36 receptor antagonist gene; ISRA, Anxiety Situations and Responses Inventory; mAchR, muscarinic receptors; MCP-1, monocyte chemotactic protein 1; mRNA messenger RNA; nAchR, nicotinic receptors; NB-UVB, narrowband ultraviolet B; PASI, psoriasis and severity index; PDT, photodynamic therapy; PPP, Palmoplantar pustulosis; PPPP, palmoplantar pustular psoriasis; PSORS 1, psoriasis susceptibility gene 1; PUVA, psoralen–ultraviolet A; SNPs, single nucleotide polymorphisms; Th17, T helper 17.