Department of Histopathology, Panjab University/A.B. Diagnostics, India
*Corresponding Author: Anubha Bajaj, Department of Histopathology, Panjab University/A.B. Diagnostics, India.
Received: February 27, 2021; Published: May 24, 2021
Citation: Anubha Bajaj. “The Bearer Blob- Pityriasis Rosea”. Acta Scientific Paediatrics 4.6 (2021): 61-66.
Pityriasis rosea is an acute, benign, self-limiting cutaneous condition composed of papules and squamous lesions. As pityriasis annotates “fine scales”, a characteristic appearance of a “herald patch” and subsequent scaly, elliptical spots are configured upon the trunk and proximal extremities, delineating a “classic Christmas tree” appearance. Pityriasis rosea or “rose coloured scale” is additionally denominated as pityriasis circinata, roseola annulata and herpes tonsurans maculosus. Majority of instances of common Pityriasis rosea manifest a classic morphology and distribution. The benign, cutaneous eruption is devoid of permanent sequelae and generally does not mandate therapeutic intervention.Disease pathogenesis
Of obscure genesis, pityriasis rosea is associated with seasonal variation. Clusters of lesions appear within communities, indicating an infective origin. Infective agents such as viruses, bacteria or spirochetes and non-infectious factors such as atopy and autoimmunity may engender the condition .
Infection of upper respiratory tract may precede the occurrence of pityriasis rosea, suggesting infection with Streptococcus. Systemic reactivation of latent human herpesvirus-6 (HHV-6) and human herpesvirus-7 (HHV-7) infection may be incriminated as etiological agents [1,2].
Pityriasis rosea-like eruptions are documented following vaccinations such as Bacillus Calmette-Guerin (BCG), influenza, swine flu (H1N1), diphtheria, smallpox, hepatitis B and Pneumococcus [1,2].
Cutaneous eruptions are observed with drugs such as gold, captopril, barbiturates, D-penicillamine and clonidine. Pityriasis rosea is common in winters with certain seasonal variation in spring and autumn.
Pityriasis rosea is associated with absence of natural killer (NK) cells and B- lymphocyte activity, indicating the predominant concurrence of T-cell mediated immunity. Elevated quantities of CD4 T-lymphocytes and Langerhans cells arise within the dermis, possibly insinuating processing and presentation of viral antigens [1,2].
Keratinocytes imbued with anti-immunoglobulin M (IgM) are discerned in pityriasis rosea which may be associated with exanthem phase of viral infection. Incidence of atypical pityriasis rosea is roughly 20% and appears contingent to clinical symptoms, biological course, distribution, magnitude or morphology of lesions [1,2].Disease characteristics
Incidence of pityriasis rosea is at an estimated 0.5% to 2%. A gender equivalence is observed. Typically, the condition arises between 10 years to 35 although children, adolescents and young adults are incriminated. Pityriasis rosea may be accompanied by atopy. Occurrence of pityriasis rosea during first 15 weeks of gestation may engender premature delivery and foetal mortality [2,3].
Pityriasis rosea- like cutaneous eruptions are associated with drug intake and multiple drugs are implicated such as captopril, gold, isotretinoin, non-steroidal anti-inflammatory agents (NSAIDs), omeprazole, terbinafine and tyrosine kinase inhibitors. Clinically, aforesaid eruptions are devoid of a herald patch. Histologically, an interface dermatitis with abundant infiltration of eosinophils is observed. Variants of Pityriasis rosea are multiple and designated as acral, inverse, purpuric, papular, follicular, vesicular and oral [2,3].
Pityriasis rosea is categorized as
Atypical variants of the condition are designated as unilateral, inverse, vesicular, papular, urticaria-like, erythema multiforme-like and purpuric [2,3].Clinical elucidation
Clinically, cutaneous eruption of pityriasis rosea typically manifests as a singular, enlarged, pink to salmon-coloured “herald patch” or “mother patch” which enhances in magnitude within 48 hours and appears at 2 centimetres to 10 centimetres. Subsequently, an acute, generalized dissemination of multiple, elliptical, scaly, papulo-squamous patches and plaques along cutaneous cleavage lines are observed which resolve within 6 weeks to 8 weeks. Relapsing and persistent variants are also observed. Lesions are predominantly situated upon the trunk and proximal extremities in concordance with Langer’s lines of cleavage displaying a characteristic “Christmas-tree" pattern [4,5].
Scaling in a collarette fashion is frequent .
Classically, a solitary, ovoid patch manifests upon the trunk as a “herald patch” which indicates disease onset. Thereafter, advancing perimeter of the patch represents as a collarette of scales [4,5].
Cutaneous eruption is preceded by prodromal symptoms of headache, sore throat, gastrointestinal manifestations, fever, malaise, lymphadenopathy and arthralgia with associated severe pruritus in around 25% instances. Herald patch appears in an estimated 50% to 90% instances and is generally situated upon the trunk, neck or proximal extremity [5,6].
Generalized cutaneous eruption demonstrates numerous, crop-like lesions occurring within one week to two weeks following the onset of herald patch. Symmetric eruptions commonly incriminate the thorax, dorsal region, abdomen, adjoining zones of neck and upper or lower extremities. Incrimination of acral sites is exceptional [4,5].
Secondary lesions occur as elliptical or ovoid macules and papules. Fine scaling and centric wrinkling, with “cigarette paper” countenance is exemplified. Characteristic lesions with “collarette” like scale, adherent peripheral edges and elevated centric region are observed. Lesion distribution is bilateral and diffuse with long axis parallel to lines of cutaneous tension [5,6].
Subsequent secondary eruption incorporates numerous miniature plaques situated upon the trunk and proximal extremities following Langer’s cleavage lines, a pattern which is referred to as a “Christmas tree” configuration when localized upon the posterior trunk [4,5].
Cutaneous rash of pityriasis rosea usually extends to up to five weeks and resolves within 8 weeks in a majority (80%) of subjects .Histological elucidation
Evaluation of cutaneous tissue specimen may be unnecessary although reveals non-specific features simulating chronic dermatitis [5,6].
Cogent histological patterns demonstrate epidermal hyperplasia, spongiosis, focal parakeratosis, superficial perivascular inflammatory infiltrate and variable red cell extravasation [5,6].
On microscopy, a superficial perivascular dermatitis is observed. Aggregates of focal parakeratosis, epithelial hyperplasia and focal epidermal spongiosis is exemplified. Epidermis demonstrates lymphocytic exocytosis, variable spongiosis, mild acanthosis and an attenuated granular cell layer. Lesions demonstrate spongiotic dermatitis along with extravasation of red blood cells and focal parakeratosis .
Extravasation of red blood cells is accompanied by perivascular infiltrate of lymphocytes, histiocytes and dermal aggregates of eosinophils. Periodic acid Schiff’s (PAS) stain demonstrates an absence of pathogenic fungi [5,6].
The scales denominate a non-specific subacute or chronic dermatitis accompanied with focal hyperkeratosis, angulated parakeratosis and minimal acanthosis. Granular cell layer is usually absent beneath foci of parakeratosis. Intra-epidermal cytoid bodies may be discerned along with minimal spongiosis. Occasional, focal acantholytic dyskeratosis is observed. Lymphoid and histiocytic inflammatory infiltrate circumscribes the vascular articulations of superficial plexus. Occasional, disseminated eosinophils and erythrocytes are enmeshed within the epidermis [5,6].Differential diagnosis
Pityriasis rosea necessitates a distinction from specific conditions such as lesions of secondary syphilis, dermatophytosis, guttate psoriasis, nummular eczema, pityriasis lichenoides chronica, cutaneous T-cell lymphoma, erythema annular centrifugal and erythema chronic migrans. Additionally, Pityriasis rosea mandates a demarcation from conditions such as erythema multiforme, Kaposi’s sarcoma, lichen planus, para-psoriasis, paediatric syphilis, pityriasis alba, seborrheic dermatitis, tinea corporis and tinea versicolor.
Histological demarcation is necessitated from diverse conditions such as dermatophytosis, pityriasis lichenoides chronica (PLC), secondary syphilis and guttate psoriasis [1,2]:
Adequate discernment of atypical variants can be challenging and mandates distinction from diverse papulo-squamous eruptions as subsequent disease management may be affected.Investigative assay
Dermatoscopy is a pertinent diagnostic manoeuvre which segregates pityriasis rosea from associated conditions. Lesions demonstrate a yellowish background, peripheral articulation of scales and patchy, loosely configured, vascular arrangements [7,8].Therapeutic options
Pityriasis rosea is a self-limiting, exanthematous condition. Contemporary therapies provide symptomatic relief and comprise of topical corticosteroids, emollients and oral antihistaminic drugs. Majority of lesions are alleviated with emollients, antihistaminic agents and topical steroids [7,8].
Macrolides and acyclovir alleviate pruritus and engender a brisk resolution of lesions. As clinical amelioration is obtained with ingestion of acyclovir, a viral aetiology is indicated [7,8].
Oral erythromycin initiates a resolution of cutaneous eruption in around 73% subjects. Narrowband ultraviolet B therapy can also be employed. Ultraviolet rays modify the cutaneous immune response [7,8].
Figure 1: Pityriasis rosea depicting a classic herald patch surrounded by fine, pink scales .
Figure 2: Pityriasis rosea delineating mild parakeratosis, spongiosis, hyperkeratosis, epidermal hyperplasia and a superficial inflammatory exudate of lymphocytes and histiocytes .
Figure 3: Pityriasis rosea demonstrating mild acanthosis, hyperkeratosis, parakeratosis, spongiosis and an upper dermal infiltrate of lymphocytes and macrophages along with few vascular articulations .
Figure 4: Pityriasis rosea exhibiting acanthosis, hyperkeratosis, parakeratosis and spongiosis along with superficial dermal inflammatory infiltrate of lymphocytes and histiocytes .
Figure 5: Pityriasis rosea enunciating acanthosis, parakeratosis, hyperkeratosis, epidermal hyperplasia, mild spongiosis and an inflammatory exudate of lymphocytes and histiocytes confined to the dermis .
Figure 6: Pityriasis rosea displaying mild spongiosis, epidermal hyperplasia, hyperkeratosis, an upper dermal chronic inflammatory infiltrate and several vascular articulations .
Figure 7: Pityriasis rosea delineating mild acanthosis, parakeratosis, hyperkeratosis, spongiosis, epidermal hyperplasia and an intense, upper dermal inflammatory infiltrate .
Figure 8: Pityriasis rosea exemplifying mild acanthosis, parakeratosis, hyperkeratosis, spongiosis and a moderate, upper dermal infiltrate .
Copyright: © 2021 Anubha Bajaj. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.