**4. Clinical findings**

#### **4.1 Cutaneous involvement**

Systemic sclerosis is divided into two subgroups, according to cutaneous involvement: limited systemic sclerosis and diffuse systemic sclerosis. If cutaneous involvement is limited to distal extremities and the face, it is classified as limited systemic sclerosis, and if the involvement is present in the truncus and extremities, it is classified as diffuse systemic sclerosis [22]. Also, systemic sclerosis sine scleroderma, of which 5% of SSc patients are affected, shows typical SSc symptoms but no fibrosis of the skin [23]. Raynaud's phenomenon is seen in more than 90% of SSc patients and is triggered by exposure to cold or emotional stress. It is characterized by white, blue, and red discoloration after triggering and most often affects the hands, feet, tongue, ears, and nose [24].

Cutaneous involvement generally consists of three phases. In the first stage, the edematous phase, non-pitting edema, facial mask appearance, and swelling of the fingers can be seen. After that comes the indurative phase, where the skin hardens and gets a shiny and tense appearance. The last stage is the atrophic phase, characterized by claw hand and sclerodactyly. Sharpening of the nose, thinning of the lips, vertical streaks around the mouth (**Figure 1**), and facial mimic loss may be seen. Skin lines or hyperpigmentation of skin areas exposed to trauma and depigmentation areas on the truncus, face, hand back, and leg fronts may develop. In some cases, the presence of depigmented areas, where perifollicular areas are preserved, results in an appearance of "salt and pepper" on the skin.

In systemic sclerosis disease-specific capillary dilatation, stumps and the presence of avascularity areas can be shown with nail bed capillaroscopy [25]. Sweat and atrophy of the sebaceous gland may lead to dry skin, flaking, and itching. Depending on the calcium accumulation in the skin, hard subcutaneous nodules may appear around the small joints of the hand (calcinosis cutis), which may open to the outside and become ulcers [26]. Ulcers (**Figure 2**) may also develop due to ischemia, trauma, and fibrotic tissue. Telangiectasia is commonly seen in SSc and is stated in the classification criteria [21].

**Figure 1.** *Nasal sharpening and perioral vertical streaks in a patient.*

**Figure 2.** *Digital ulcer in a patient.*
