Capillaritis and Pigmented Purpuric Dermatoses

Pigmented purpuric dermatoses (PPD) are a group of conditions characterised by extravasation of red cells andmarked haemosiderin pigmentation of the skin. It has also been called ‘capillaritis’, although there is no evidence of a true vasculitis. The hallmark of a PPD is its characteristic orange-brown, speckled, cayenne pepper–like discoloration. The etiology of PPD remains unknown. However, past literature work has implicated a number of factors that may affect the appearance of the condition. These factors include venous hypertension, exercise and lower limbs dependence. Drugs such as Aspirin, Glipizide, Thiamine and Interferon-alfa are believed to be associated with the initiation of PPD. Disorders such as diabetes mellitus, rheumatoid arthritis, hepatic disease and hyperlipidemia are also considered to have a correlation with this condition.

A number of clinical patterns are recognised all demonstrating a similar histologic appearance. These includeSchamberg’s disease (or progressive pigmented purpuric dermatosis), purpura annularis telangiectodes (Majocchi disease), pigmented purpuric lichenoid dermatosis of Gougerot and Blum, lichen aureus, itching purpura and eczematoid-like purpura of Doucas and Kapetanakis.

These subclass all share common histopathologic features, examples including lymphocytic inflammation, red blood cells extravasation and haemosiderin deposition. Especially in the Gougerot-Blum and Eczematoid-like purpura of Doucas and Kapetanakis class, the epidermis may show spongiosis or parakeratosis. Older lesions tend to be less inflammated and extravasated RBC may no longer be found present at the affected area. The perivascular lymphocytic infiltrate of T cells is centered on the superficial dermal venules which show signs of endothelial swelling and narrowing of the lumen. Extravasation of red cells with marked haemosiderin deposition in macrophages is also found. A granulomatous variant of PPD has also been reported.

Pathogenesis of this group of conditions is unknown however, a number of hypotheses have been put forward. Weakness or disturbance of the cutaneous blood vessels leading to RBC extravasation and capillary fragility has been implicated. Deposition of IgM, IgA (immunoglobulins) or C3, C1q and Langerhans cells have all been implicated in causing inflammation which leads to red cells extravasation.

Pathogenesis are classed under 3 different perspectives. The first is due to the weakness or disturbance of thecutaneous blood vessels leading to RBC extravasation and capillaries becoming fragile. However, this is not hypothesised to be the initiation of inflammatory (which does occur in these disorders).Second is due to the humoral immunity, involving T cells and B cells in the systemic circulation. It is suggested that pathogenesis associated with the vascular deposition of IgM, IgA (immunoglobulins) or C3 and C1q (complimentary cells). The third mechanism is associated with the cellular immunity, once again involving T and B cells, The pigmented purpuric dermatoses consists of lymphocytes, macrophages and Langerhans cells. This causes inflammation occurrence and gradually to the subsequent leakage of erythrocytes. Aiba and Tagami performed a study and concluded that specifically Langerhans cells if likely to play an important role in the pathogenesis.

Venous hypertension, exercise, stasis and gravitational dependence are important cofactors that appear to influence disease presentation. Other associations are hypersensitivity to food dyes and preservatives such as tartrazine, clothing dye dermatitis, and drug hypersensitivity reactions to carbamazepine, meprobamate, chlordiazepoxide, furosemide, nitroglycerin, vitamin B1, glipizide, and topical fluoruracil. Differential diagnoses include mycosis fungoides, stasis pigmentation, and scurvy.

Schamberg Disease - May also be known as Progressive Pigmentary Dermatosis. Schamberg disease may occur at any age but is more common among males. The average age of Schamberg disease occurrence is amongst 40 years old patients. Its occurrence has been associated with leaky blood vessel walls. The lower limbs are mostly affected but may also develop in other areas of the body. Irregular plaques and patches of orange-brown pigmentation when developed will spread slowly. The lesions are chronic and may persist for years but some may spontaneously clear. Associations include venous disease, occult odontogenic infections, food additive and food coloring hypersensitivity. There are generally no symptoms shown in patients except for a slight feel of itchness from time to time. Symptoms may be controlled using topical steroids. Kano et.al used pentoxifylline at a dosage of 300mg per day for 8 weeks in 3 patients who all showed significant improvement within 2-3 weeks. However, Baskak & Ergin used double the dosage of pentoxifylline and found it not to be useful.

Itching purpura of Lowenthal – Also known as Disseminated Pruriginous Angiodermatitis. Itching purpura is characterised by more generalised skin involvement. The lesions are much more extensive, and patients typically complain of severe pruritus. Lesions are observed to be red-brown in colour. The average age of Itching Purpura occurrence is amongst middle aged people (50 years old). It is more commonly found in males. Khaki-colour clothing dermatitis and contact dermatitis to rubber are implicated.

Lichen aureus - May also be known as Lichen Purpuricus. Usually occurs ranging from the 20s to 30s age gap. It presents as a solitary golden plaque or a localized group of lesions containing purpura. Some patients report it to be painful. Colour may vary from yellow to purple. It may be thought to be a ‘bruise’ for many years. Lichen aureus is most commonly found at the lower legs area, where there is an underlying incompetent perforator. Treating the underlying perforator incompetence will help in resolution of the lesion.

Majocchi disease - Also known as Purpura Anularis Telangiectoides. This disease usually occurs in children and young adolescence, more commonly in young adult females (around 30 years of age). This is characterized by small (having a diameter ranging from 1 to 3cm) annular plaques of purpura that contain prominent telangiectasia.Linear and irregular shaped patterns may also be seen. It may be found at any site. CVI is thought to be an association. Lesions found localised symmetrically, commonly on the lower extremities but may also extend to the trunk and upper area of the body.

Pigmented purpura lichenoid dermatosis of Gougerot and Blum - Lichenoid change is yet another clinical variant. The lesions seen are observed as orange-red and can be seen growing individually or grouped. It mainly affects middle-aged men, approximately 40 years of age. This sub-type has not been reported in children. The lesions arelichenoid purpuric papules mostly found on the lower legs. Patches appear thickened and itchy, being described similar like eczema. Contact dermatitis to oils and to dyes are thought to play a role in its pathogenesis. Certain drug hypersensitivities may have a similar presentation.

Eczematoid-like purpura of Doucas and Kapetanakis - Also known as Disseminated Pruriginous Angiodermatitis. Most common in adult females (approximately 40 years old) and is more generalised. Different comparing with Schamberg’s disease because of the presence of focal spongiosis and scale crust. The onset pigmented eruption of Schamberg’s and Majocchi’s disease are described as insidious whereas Doucas and Kapetanakis, Gougerot and Blum, Itching Purpura and Lichen Aureus are more abrupt. Case report by Laufer that ascorbic acid (vitamin C) 500mg twice a day and a bioflavonoid rutoside 50mg twice a day is able to treat this rash, with no reccurrence.

Linear Dermatoses is a rare form of PPD.

Linear (Unilateral) Dermatoses – May also be termed quadrantic capillaropathy. Lesions found to be asymptomatic and occurs on the lower limb, torso and rarely midline cuttoff. Treatment generally effective spontaneously within 3 months in all cases reported. This condition generally affects young patients however though, because of the rarity, the causes are not yet known.