**6. Clinical features**

All patients with PV develop painful erosions of the mucosal areas, especially oral mucosa. Oral lesions are the first finding in 50–70% of cases and occur during the course of the disease in 90% of patients [18]. More than half of patients also develop flaccid blisters and extensive cutaneous erosions. PV is divided into two

subgroups according to the area of involvement: (1) mucosal dominant type, in which mucosal erosions are prominent and skin involvement is minimal; and (2) mucocutaneous type with extensive cutaneous bullae and erosions in addition to mucosal involvement [19].

Mucosal erosions usually precede the cutaneous manifestations of the disease. In some cases, oral ulcers may be the only manifestation of the disease. Intact bullae are rare because they are fragile and break easily. Although diffuse or widespread erosions can occur anywhere in the oral cavity, the most common sites are the buccal and palatine mucosa, lips and gingiva. Erosions are numerous and found in varying sizes and irregular shapes; they extend peripherally and there is usually a delay in reepithelialization. Gingival involvement is seen as desquamative gingivitis. There are fissured hemorrhagic crusts that can extend up to the vermilion border in lip involvement. Involvement of the oral mucosa may impair nutrition and therefore the general condition of the patient [20]. Lesions of the nasal mucosa lead to hemorrhagic crusts. Apart from the oral and nasal mucosa, the oropharynx, esophagus, conjunctiva, larynx, urethra, vulva, vagina, penis and anus are other mucosal involvement areas.

Skin involvement may be localized or generalized. Often there are clear flaccid blisters on normal or erythematous skin. The contents of the bullae are clear at first, but over time they may become turbid, seropurulent and hemorrhagic. The bullae may coalesce and rupture quickly to form painful erosions that bleed easily. Erosions are covered with crusts that heal slowly in a short time. PV skin lesions can be seen anywhere on the body, but the involvement of the trunk, groin, axilla, scalp and face is common, while the palms and soles of the feet are usually protected.

Due to the abundance of Dsgs in the hair follicles, the scalp is a unique place for pemphigus. In the course of pemphigus, scalp involvement is observed in up to 60% of patients. Erosions, crusts and scaly plaques can sometimes lead to alopecia. Effortless removal of anagen hairs in a pull test is a sign of high disease activity [21].

The flaccid nature of the blisters seen in PV are due to intraepidermal acantholysis caused by anti-Dsg antibodies. Due to the loss of cohesion in the epidermis, it moves easily laterally in patients with active disease (Nikolsky sign) by applying light pressure or friction to the upper layers of the skin [19]. Direct Nikolsky (Asboe–Hansen sign) is the spreading of the blister to adjacent skin by applying light pressure on a blister, indirect Nikolsky is the application of rubbing to clinically normal-appearing skin to cause separation as a result of rubbing. These findings are not 100% specific for the diagnosis, but their presence suggests PV. These signs clinically represent acantholysis or loss of cell adhesion. It can also be found in other forms of pemphigus, as well as in toxic epidermal necrolysis [19, 20].

Pruritus is rare. Both mucosal and skin lesions heal without scarring, but hyperpigmentation in the affected areas may persist for months, especially in dark-skinned patients. PV is a chronic disease with periods of remission and exacerbation. Without appropriate treatment, PV can be fatal because extensive skin involvement may result in loss of epidermal barrier function and lead to loss of body fluids, malnutrition, and secondary infections. Secondary bacterial infection is one of the most common complications and can progress to septic shock [19, 20].

Among the rare clinical findings of PV; isolated crusty plaques on the face and scalp, foot ulcers, dyshidrotic eczema, macroglossia, nail dystrophy, paronychia and subungual hematomas can be counted. Nail involvement usually occurs when the disease is severe and in most cases responds partially or completely to systemic therapy [1, 19]. In the literature, two patients with cervical pemphigus vulgaris with symptoms as postmenopausal bleeding have been reported [22].
