2nd July 2023

Cutaneous Vasculitis and Connective Tissue Disorders

Cutaneous Vasculitis 

A group of disorders resulting in inflamed blood vessels in the skin. There are many different causes and a wide variety of clinical presentations. It is thought that the inflammatory response in the blood vessel wall could be a result of:

• Direct injury from bacteria or viruses
• Indirect injury through activation of antibodies
• Indirect injury through activation of complement pathways

There are many different causes of cutaneous vasculitis, including infection, autoimmune conditions and vasculitides, medications, and malignancy. In some cases, it can be associated with systemic vasculitis. However, in many cases, there is no underlying cause, and the disease will be self-limiting.

It can be classified according to which type of blood vessel it affects, such as capillaries, small, medium, or large vessels; however, large vessel vasculitis very rarely results in cutaneous features. The main presenting feature of small vessel vasculitis is pigmented and often palpable purpura, whereas nodules and a rash known as livedo reticularis are more associated with medium vessel vasculitis.

Diagnosis is based on the clinical appearance but can be supported with a skin biopsy and blood tests to exclude other possible underlying causes. Treatment is through identification and removal of the underlying cause, including treatment of systemic vasculitis if it is a manifestation of a systemic disorder. Initial management of the rash when no underlying cause is identified is cold avoidance.

Connective Tissue Disorders (CTDs)

CTDs are a heterogenous group of conditions that occur because of problems with collagen, and some have a vascular component as well. There are many CTDs, often similar in presentation, and can largely be split into inherited (such as Marfan’s syndrome and Ehlers-Danlos syndrome) and acquired CTDs (there are many, for which three are focused on below).

Cutaneous Lupus Erythematosus (CLE)

CLE is an uncommon group of skin disorders and occurs from autoimmune processes. It can be associated with systemic lupus erythematosus (SLE). There are many different types of CLE. Some of the key forms have been described below:

A table summarising the key features in different forms of CLE.

Systemic Sclerosis

An autoimmune condition characterised by skin and internal organ fibrosis and vascular disease. There are two main subtypes according to the distribution of skin involvement: diffuse cutaneous systemic sclerosis (skin involvement across the whole body and early organ fibrosis) and limited cutaneous systemic sclerosis (skin involvement is limited to the face, hands, and feet).

The main skin manifestations are sclerodactyly, thickening and tightness of the skin of the fingers and toes, Raynaud’s phenomenon, telangiectasia on the face, chest and palms, and calcinosis on digits and extensor surfaces of arms. Patients will often exhibit microstomia, which can be defined as reduced interlabial distance of <4.5cm. In severe cases, patients can develop digital ulcers, which can result in dry gangrene and eventual loss of the tips of the fingertips.

Dermatomyositis

A rare multisystem disorder that can affect the skin as well as muscles and blood vessels. The exact underlying aetiology is not well understood. Triggers include medications, malignancy, viral infections, and certain trades, such as silica exposure. Additionally, most patients have disease-associated antibodies suggesting an autoimmune component, with ANA being the most common and anti-Mi-2 being the most specific. Skin manifestations can often have similarities with those seen in other CTDs, such as photosensitivity, calcinosis, and Raynaud’s phenomenon. More characteristic skin manifestations include Gottron’s papules and a heliotrope rash. The heliotrope rash presents on the face and upper eyelids as a bilateral lilac coloured discolouration. Gottron’s papules are characteristic purple papules and plaques that can be seen over the small joints of the hands.