Urticarial rash (hives) is seen in several bacterial and viral infections, so COVID-19 is no exception. These rashes are more commonly found in the trunk and limbs, relatively sparing the acral sites. Systemic corticosteroids are a therapeutic option for urticarial rash induced by COVID-19.[4]
Confluent erythematous rash
The erythematous rashes (redness caused by increased blood flow through skin capillaries) seen in COVID-19 are mostly present on the trunk and limbs, and associated with itching.[4] Exanthems induced by viruses other than COVID-19 and drug reactions should be considered as differential diagnosis in the case of erythematous rashes.[4]
Livedo reticularis
Livedo reticularis refers to slowing of blood flow, leading to desaturation of blood and bluish discolouration of the skin. This type of skin rashes may be seen in cold-induced vasoconstriction as seen in polycythemia or other causes leading up to focal impairment of blood flow.[4]
Histopathological hallmarks
From the histological (microscopic anatomy) perspective, several features of the maculopapular lesion have been recognized. Maculopapular lesions exhibit superficial perivascular dermatitis with lymphocytic infiltrate and dilated vessels in the papillary and mid dermis with neutrophils, eosinophils, and nuclear debris. Epidermis revealed dispersed foci of hydropic changes, accompanied by minimum acanthosis, subcorneal pustules, slight spongiosis, Basal cellvacuolation, and foci of parakeratosis.[6] A lichenoid pattern with eosinophils' presence on biopsy of skin lesions has been observed in some patients.[7]