Annular lesions in dermatology.

Annular lesions are extremely common and striking in appearance, but can also be misleading. The term “annular” stems from the Latin word “annulus,” meaning ringed. Herein, we enumerate different presentations of annular lesions.

Annular lesions are classified as Table 1.

Table 1

Causes for annular lesions

Tinea corporis is characterized by annular or polycyclic lesions with erythematous and vesicular or scaly border with central clearing[1] Figure 1]. Tinea imbricata is an unusual form of tinea corporis caused by Trichophyton concentricum, which is characterized by itchy, non-inflammatory, concentric rings.[2] In bullous impetigo, occasionally the bullae spreads peripherally with central clearing, producing annular lesions called Impetigo Circinata. Varnish like yellow crust gives clue to diagnosis.[3] Secondary syphilis may be present as annular lesions. A thin white ring of scales on the surface of the lesion (Biette's collarette) is a valuable sign.[4]

Figure 1

Tinea corporis showing peripheral spreading with central clearing

In leprosy, annular lesions usually represent borderline cases. There is loss of sensation over the lesion.[5] Lupus vulgaris may assume annular shape with central thin superficial scar and apple jelly nodule at the edge of the lesion[3] [Figure 2]. Cutaneous leishmaniasis presents with small furuncle at the site of inoculation with gradual peripheral spreading and central crusting giving annular appearance.[6] In secondary stage of Trypanosomiasis, transient erythematous or urticarial rashes, with circinate and annular pattern, will develop on the trunk.[7] Erythema multiforme has target lesions which has three zones: a central area of dusky erythema or purpura, a middle paler zone of oedema, and an outer ring of erythema with well-defined edge.[8]

Figure 2

Lupus vulgaris

Chronic plaque psoriasis (psoriasis vulgaris) plaque, sometimes extends peripherally, the central part undergoes clearing, causing the formation of annular lesions called annular psoriasis, [Figure 3] which has good prognosis.[9] Subacute annular pustular psoriasis is a generalized type of pustular psoriasis characterized by multiple annular lesions with erythema, scaling, and pustules at the periphery.[10] Annular lichen planus is violaceous in color with very narrow rim of activity and a depressed, slightly atropic center found on penis.[11] Annular lichenoid dermatitis is a distinct entity in youth.[1213] Herald patch of pitryiasis rosea is an oval or round lesion with typical collarette of scale at the margin.[14] Porokeratosis of Mibelli presents as a dry annular plaque surrounded by a raised, fine keratotic wall with characteristic furrow in it.[15]

Figure 3

Annular psoriasis. Central cleared zone is often immune to psoriasis

Bullous pemphigoid, in the early stage presents as urticarial lesions. The erythematous component may become serpiginous, with peripheral blister.[16] Subcorneal pustular dermatoses (Sneddon-Wilkinson disease) presents as oval, peasized flaccid pustules which rupture easily, and tend to coalesce, forming annular or serpiginous patterns with a scaly edge. Characteristically, pus accumulates in the lower half of a fully developed pustule, leaving clear fluid in the upper half. Linear immunoglobulin A (IgA) dermatosis presents as lesions comprising urticated plaques and papules, and annular, polycyclic lesions often with blistering around the edge, the string of pearls sign [Figure 4][17].

Figure 4

Linear IgA dermatosis showing string of pearls appearance

Granuloma annulare presents as closely set, skin-colored, firm, smooth asymptomatic papules arranged in a ring-like fashion [Figure 5]. Lesions usually resolve on its own without leaving any telltale mark.[18]

Figure 5

Granuloma annulare in a diabetic

Subacute cutaneous lupus erythematosus (SCLE) [Figure 6] and Neonatal lupus erythematosus (NLE) presents as annular polycyclic lesions. 95% cases of NLE and 70% cases of SCLE show positivity for Anti-Ro/SSa auto antibodies.[1920]

Figure 6

Sub acute lupus erythematosus

Petaloid form of seborrhoic dermatitis sometimes assume annular pattern consisting of multiple circinate patches, with a fine branny scaling in their centers, and with dark-red papules with larger greasy scales at their margins.[21] After an acute phase, nummmular or discoid eczema may progress towards a less vesicular and more scaly stage, often with central clearing, and peripheral extension, causing ring-shaped or annular lesions. Nummular patches may accompany the more typical dry, erythematous scaling patches of atopic dermatitis. Meyerson described two patients with multiple pruritic, papulosquamous lesions surrounding melanocytic naevi which resolved spontaneously and termed it as Meyerson phenomenon or Halo eczema.[22]

Figurate erythemas are a group of dermatoses mostly developing in response to an underlying condition. Erythema gyratum repens is characterized by multiple, annular, concentric, rapidly growing erythematous plaques with a trailing scale resembling wood grain.[23] Erythema anulare centrifugum (EAC) presents as multiple, annular, polycyclic, slowly growing erythematous plaques with a trailing scale. It is usually pruritic and often spares palms and soles.[24] Erythema chronicum migrans is a skin finding at early stages of borreliosis, and erythema marginatum is the rapidly disappearing erythematous rash of acute rheumatic fever.[25] Annular erythema of infancy has clinical morphology of EAC but occurs in infancy.[26] Erythema gyratum atrophicans transiens neonatale is now felt to be a variant of NLE.[27] Autosomal dominant annular erythema is noted in a family and termed as familial annular erythemas.[28] Neutrophilic and vasculitic annular eruptions includes acute hemorrhagic oedema of infancy, erythema elevatum diutinum, urticarial vasculitis, Henoch-Schönlein purpura, and some cases of leukocytoclastic vasculitis associated with myeloma, inflammatory bowel disease or pregnancy.[29]

Basal cell carcinoma or rodent ulcer sometimes present as slowly expanding annular plaque with translucent or pearly, raised periphery with central ulceration.[30] Mycosis fungoides in the initial phase of T1/IA andT2/IB may present with annular plaques.[31]

Fixed drug eruptions presents as well-defined erythematous, violaceous or hyperpigmented macule with erythematous ring around it [Figure 7]. It frequently involves oral mucosa, glans penis, hands, and feet.[32]

Figure 7

Fixed drug eruption with erythematous ring. Sometimes erythematous ring around old lesion is the only sign of recurrence

Purpura annularis telangiectoides or Majocchi's disease is a chronic pigmented purpuric dermatosis characterized by punctiform red patechial telangiectatic patches, with centrifugal growth giving annular or serpiginous appearance. Cayenne pepper spots are characteristic.[33] Annular purpura which may occur when the skin is struck by table tennis ball (ping-pong patch) and in step aerobics.[3435]

Annular lesions may also rarely be found in lupus erythematosus (LE),[36] chronic variant of sweet syndrome[37] and neutrophilic eccrine hidradinitis.[38]