Coexistence of Riehl’s Melanosis, Lupus Erythematosus and Thyroiditis in a Patient

Abstract

Introduction Riehl’s melanosis (RM) is an acquired hyperpigmentation disorder, presenting diffused and reticulate brownish-gray pigmentation, preferentially on the face and neck. RM overlaps with systemic lupus erythematosus (SLE) and Hashimoto’s thyroiditis has never been reported. Case We report a case of RM patient accompanied with SLE and Hashimoto’s thyroiditis of primary hypothyroidism. Progressing, diffuse, symmetric, and reticular hyperpigmentation was seen on the face, neck, and upper limbs, manifesting as typical melanosis. Skin microscopy showed diffuse black-pepper-like changes and telangiectasias. The diagnosis of SLE and primary hypothyroidism were confirmed by follow-up investigations. The hyperpigmentation turned notably lighter after 14 months of treatment with prednisone, hydroxychloroquine, and L-thyroxine. Discussion The exact pathogenesis of RM is unclear and exposure to coal tar dyes, ultraviolet, and fragrance fixatives in cosmetics are believed to be contributing factors, while some cases involve no triggers. It is not impossible that RM is a rare skin manifestation of SLE that has never been reported. The skin hyperpigmentation in this patient was not triggered by thyroid disease. Conclusion RM could be a skin manifestation of autoimmunity. Coexistence of RM, lupus erythematosus and thyroiditis in the same patient is rare and has never been reported.

Unveiling the mystery of Riehl's melanosis: An update from pathogenesis, diagnosis to treatment

“…Besides the possible role of anti‐SSA (Ro) in the Riehl's melanosis‐like eruptions associated with primary Sjögren's syndrome, Takeo et al (2016) reported an association with specific types of human leukocyte antigen (HLA) and infiltrating lymphocytes in three similar cases, carrying the presumption that specific HLA loci HLA‐A2, DPA1 (02:02), and DPB1 (05:01) represent the specific HLA subset of pigmented cosmetic dermatitis‐like eruptions, while subsets of T cells infiltrated in the dermis are mainly CD8 and CD45RO. Moreover, the coexistence of Riehl's melanosis with autoimmune thyroid disease was reported by Lai et al (2022) and Song et al (2018). They speculated the elevation of adrenocorticotrophic hormone (ACTH) and anti‐TSH receptor antibody (TRab) could stimulate the production of cAMP, promoting the proliferation and differentiation of melanocytes, leading to the hyperpigmentation of skin (Lai et al, 2022).…”

“…Riehl's melanosis/Riehl's melanosis‐like pigmentation has been constantly reported coexisting with other diseases, for instance, lichen planus (Seike et al, 2003), Idiopathic choroidal neovascularization (CNV) (Wu & Li, 2007), acquired immune deficiency syndrome (AIDS) (Hanada et al, 1994), Sjogren's syndrome (SS) (Miyoshi & Kodama, 1997; Takeo et al, 2016), lupus erythematosus, and thyroiditis (Lai et al, 2022). Despite the lack of explanation for these cases, experts hypothesized that Riehl's melanosis was a cutaneous manifestation of autoimmunity.…”

“…Moreover, their results uncovered that CCN1 promotes melanogenesis via binding to the integrin a6b1 receptor on NHEMs, which activates the p38 mitogen-activated protein kinase (MAPK) and ERK1/2 signaling pathways, resulting in the activation of microphthalmia-associated transcription factor (MITF), tyrosinase related protein-1(TRP-1), and tyrosinase.6.2 | Comorbidity with autoimmune disordersAs mentioned in the pathogenesis of Riehl's melanosis, other autoimmune disorders accompanied by Riehl's melanosis may indicate the potential "coworker" relation between these diseases.Besides the possible role of anti-SSA (Ro) in the Riehl's melanosislike eruptions associated with primary Sjögren's syndrome,Takeo et al (2016) reported an association with specific types of human leukocyte antigen (HLA) and infiltrating lymphocytes in three similar cases, carrying the presumption that specific HLA loci HLA-A2, DPA1 (02:02), and DPB1 (05:01) represent the specific HLA subset of pigmented cosmetic dermatitis-like eruptions, while subsets of T cells infiltrated in the dermis are mainly CD8 and CD45RO. Moreover, the coexistence of Riehl's melanosis with autoimmune thyroid disease was reported byLai et al (2022) andSong et al (2018). They speculated the elevation of adrenocorticotrophic hormone (ACTH) and anti-TSH receptor antibody (TRab) could stimulate the production of cAMP, promoting the proliferation and differentiation of melanocytes, leading to the hyperpigmentation of skin(Lai et al, 2022).ACTH is the activator of melanocortin 1 receptor (MC1R), which can activate adenylate cyclase, and increase intracellular cAMP synthesis.…”

“…Moreover, the coexistence of Riehl's melanosis with autoimmune thyroid disease was reported byLai et al (2022) andSong et al (2018). They speculated the elevation of adrenocorticotrophic hormone (ACTH) and anti-TSH receptor antibody (TRab) could stimulate the production of cAMP, promoting the proliferation and differentiation of melanocytes, leading to the hyperpigmentation of skin(Lai et al, 2022).ACTH is the activator of melanocortin 1 receptor (MC1R), which can activate adenylate cyclase, and increase intracellular cAMP synthesis. The major biological effects of cAMP are mediated through cAMP-dependent protein kinase A (PKA) which results in the phosphorylation of cAMP response element-binding protein (CREB) and the induction of MITF gene expression.…”